Stocking calculator

Clown killifish with Cherry shrimp, one setting only: The most precise shrimp answer any source on this site has given. Aquarium Co-Op: clown killifish do not seem to eat adult dwarf shrimp, but baby shrimp are fair game.

Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so both halves of that sentence apply to the same tank at the same time. The water allows it: temperature meets from 68 to 79 and hardness from 71 to 143 ppm.

A colony survives and a generation does not, which is a caution rather than a refusal because our source says so in those terms.

Clown killifish with Betta, one setting only: Aquarium Co-Op names the betta as a tank mate whose compatibility depends on individual temperament, which is the only pairing it hedges. Our betta record carries one source that will not put a betta in a community tank at all against another naming five tank mates, so both records leave the same question open.

The water is the other half: that record prints around 80 °F and this one stops at 79, so the two published figures meet at nothing, and the tolerance range on the betta record, 72 to 86, is what the pairing would have to run on.

Clown killifish with Nerite snail, one setting only: Aquarium Co-Op names snails among the tank mates for this fish, and our own two records will not support it. Our nerite snail record carries pH 7.5 to 8.5 and this record carries 4.0 to 7.0, so the two ranges do not meet at all, and the hardness only meets if both are read at their extremes.

A snail needs carbonate and this fish is published for water with almost none, which is the same failure our platy record found from the opposite end of the pH scale.

Least killifish with Betta, never: Seriously Fish again, and here the fish is the right size to be food rather than the wrong size to be safe. Our betta record is 2.4 to 2.8 inches and runs 72 to 86 °F, containing this record’s whole band, so there is no setting that separates them.

Seriously Fish names the mates it would accept instead and three of them have records here: dwarf Corydoras, Otocinclus and freshwater shrimp, which on this site is our cherry shrimp, amano shrimp and ghost shrimp records.

Pea puffer with Nerite snail, never: This is diet rather than temperament. Seriously Fish states the puffer needs small snails with the shell on regularly, and Aquarium Co-Op names live pest snails among what it eats. A nerite is a snail bought to live for one to two years, not a feeder.

Pea puffer with Cherry shrimp, one setting only: Ours, and the same shape of problem. Seriously Fish allows some freshwater shrimp with this fish; Aquarium Co-Op says no clean up crew. Our own shrimp record adds the figure that decides it for us: the young hatch at about a millimeter, and this is a fish that eats snails out of their shells.

African dwarf frog with Cherry shrimp, never: Aquarium Breeder is unambiguous: African dwarf frogs will eat all your dwarf shrimp, it is simply inevitable. Our cherry shrimp record is a dwarf shrimp, and its own page is built around breeding a colony.

The same source gives amano and ghost shrimp a chance because they can grow up to 2 inches, which is the size of the frog itself.

Cherry shrimp with Betta, never: Aquarium Co-Op states bettas are notorious for going after shrimp. Our record marks the pairing never rather than risky, and the reason is that the young hatch at about a millimeter.

Ghost shrimp with Betta, never: The same verdict as our cherry shrimp record and a different reason for it. No source on this record names the betta, but two of them state that ghost shrimp are bought as feeders for larger aggressive fish, and at 1 to 1.5 inches this animal is the same size as the shrimp our betta guide already refuses.

Ramshorn snail with Pea puffer, never: Fishkeeping World names puffers among the animals that eat ramshorn snails. Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is the other half of the same sentence: a ramshorn at 18 to 25 mm is the small snail that instruction is about.

That record already refuses our nerite snail and is cautioned against our assassin snail, and this is the pairing its own diet row was written for.

Clown killifish with Cherry shrimp, one setting only: The most precise shrimp answer any source on this site has given. Aquarium Co-Op: clown killifish do not seem to eat adult dwarf shrimp, but baby shrimp are fair game.

Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so both halves of that sentence apply to the same tank at the same time. The water allows it: temperature meets from 68 to 79 and hardness from 71 to 143 ppm.

A colony survives and a generation does not, which is a caution rather than a refusal because our source says so in those terms.

Clown killifish with Betta, one setting only: Aquarium Co-Op names the betta as a tank mate whose compatibility depends on individual temperament, which is the only pairing it hedges. Our betta record carries one source that will not put a betta in a community tank at all against another naming five tank mates, so both records leave the same question open.

The water is the other half: that record prints around 80 °F and this one stops at 79, so the two published figures meet at nothing, and the tolerance range on the betta record, 72 to 86, is what the pairing would have to run on.

Clown killifish with Nerite snail, one setting only: Aquarium Co-Op names snails among the tank mates for this fish, and our own two records will not support it. Our nerite snail record carries pH 7.5 to 8.5 and this record carries 4.0 to 7.0, so the two ranges do not meet at all, and the hardness only meets if both are read at their extremes.

A snail needs carbonate and this fish is published for water with almost none, which is the same failure our platy record found from the opposite end of the pH scale.

Least killifish with Betta, never: Seriously Fish again, and here the fish is the right size to be food rather than the wrong size to be safe. Our betta record is 2.4 to 2.8 inches and runs 72 to 86 °F, containing this record’s whole band, so there is no setting that separates them.

Seriously Fish names the mates it would accept instead and three of them have records here: dwarf Corydoras, Otocinclus and freshwater shrimp, which on this site is our cherry shrimp, amano shrimp and ghost shrimp records.

Guppy with Ember tetra, one setting only: Ours, from the published pH rows rather than from anything either source says: the guppy floor is 7.0 and the ember tetra ceiling is 7.0, so the two records meet at one number and share no range at all. A tank held exactly at neutral suits both and any drift suits one.

Honey gourami with Betta, one setting only: Ours, and a caution rather than a refusal because the disagreement sits on the other record. The water is not the problem: 74 to 81 here against 72 to 86 there, and both animals are anabantoids that breathe air and build bubble nests.

What makes the pairing a question is that our betta record carries one source saying never to keep a betta in a community tank against another that names five tank mates. Nothing on either record names the other animal, so the arithmetic allows it and the betta’s own sources have not settled whether it belongs in a community at all.

Pea puffer with Nerite snail, never: This is diet rather than temperament. Seriously Fish states the puffer needs small snails with the shell on regularly, and Aquarium Co-Op names live pest snails among what it eats. A nerite is a snail bought to live for one to two years, not a feeder.

Pea puffer with Otocinclus, one setting only: Ours, from a direct contradiction: Seriously Fish names Otocinclus spp. as compatible with this fish, and Aquarium Co-Op says no algae eaters at all. We take the stricter side and mark it a caution rather than a refusal, because one of the two sources recommends the pairing and we are not going to pretend it does not.

Pea puffer with Rabbit snail, never: The snail record names this fish. FishioHub lists puffers, large loaches and assassin snails as incompatible with rabbit snails, and this record already carries a source putting snails with the shell on in its own diet row. The bands overlap from 78 to 82 °F.

Pea puffer with Cherry shrimp, one setting only: Ours, and the same shape of problem. Seriously Fish allows some freshwater shrimp with this fish; Aquarium Co-Op says no clean up crew. Our own shrimp record adds the figure that decides it for us: the young hatch at about a millimeter, and this is a fish that eats snails out of their shells.

Platy with Ember tetra, one setting only: Two problems at once. Our ember tetra record carries pH 5.5 to 7.0 against 7.0 to 8.0 here, so the two meet at a single point, and hardness 18 to 179 ppm against 214 to 321, which do not meet at all.

Fishkeeping World adds a warning from the other direction: long-finned platy varieties should not be kept with renowned fin-nippers such as tiger barbs and tetras. Our ember tetra record stores peaceful, shoaling from a source describing that species, so the family warning and the species statement point different ways, and the cell prints both.

Platy with Otocinclus, one setting only: Ours, from two published rows. Our otocinclus record carries 36 to 179 ppm against 214 to 321 here, so there is no shared hardness, while the pH meets from 7.0 to 7.5 and the temperature from 70 to 77.

No source on either record names the pairing. It is the same failure as the bristlenose cell and it is worth printing twice, because the reason this fish is hard to pair is one row that most keepers never test.

African dwarf frog with Cherry shrimp, never: Aquarium Breeder is unambiguous: African dwarf frogs will eat all your dwarf shrimp, it is simply inevitable. Our cherry shrimp record is a dwarf shrimp, and its own page is built around breeding a colony.

The same source gives amano and ghost shrimp a chance because they can grow up to 2 inches, which is the size of the frog itself.

Assassin snail with Nerite snail, never: Named, and by the most detailed source on this record. Asked whether assassin snails eat mystery and nerite snails, Aquarium Breeder answers: eventually, yes, and it says larger snails are taken if the assassins gang up.

Aquarium Source restricts the prey to snails smaller than themselves, which a 0.5 to 1.5 inch nerite is not always, and AquaticMotiv puts bigger snails on the safe list. So one source refuses the pairing outright and two allow it with a size condition, and the record refuses it: our nerite snail record is the animal a keeper paid a premium for, and one source we cite says it goes eventually. It is the third refusal against that record, after the pea puffer and the clown loach.

Assassin snail with Cherry shrimp, one setting only: Every source that addresses shrimp says yes with a condition attached, and no two conditions match. Aquarium Breeder: yes, they do eat shrimp, but only the weak, the sick, or the ones that are molting.

Aquarium Source names shrimp fry among its foods. AquaticMotiv: only smaller or baby shrimp, while larger or adult shrimp are typically safe. Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so the adults sit on the safe side of all three conditions and every generation after them does not.

The cell is a caution because that is exactly what our sources describe: not a refusal, and not a pairing anybody should call safe either.

Assassin snail with Pea puffer, never: Named from both sides, which settles a cell the first draft of this record marked a caution. Aquarium Breeder lists pufferfish among the animals that will eat an assassin snail, alongside cichlids, loaches and goldfish.

Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is why that record already refuses our nerite snail. So one source says the puffer eats this snail and our own record says the puffer needs snails: the two statements are the same statement. The bands would have allowed it, since that record runs 74 to 82 °F against 75 to 80 here.

Cherry shrimp with Betta, never: Aquarium Co-Op states bettas are notorious for going after shrimp. Our record marks the pairing never rather than risky, and the reason is that the young hatch at about a millimeter.

Ghost shrimp with Betta, never: The same verdict as our cherry shrimp record and a different reason for it. No source on this record names the betta, but two of them state that ghost shrimp are bought as feeders for larger aggressive fish, and at 1 to 1.5 inches this animal is the same size as the shrimp our betta guide already refuses.

Rabbit snail with Assassin snail, never: Two sources name assassin snails among the animals to avoid with this one. Aquarium Breeder lists them alongside crayfish, cichlids, loaches and goldfish, and Fish Laboratory lists bettas, tiger barbs, cichlids, crayfish and assassin snails.

Our own assassin snail record carries a source saying it hunts snails and does not eat algae, and the bands overlap from 78 to 80 °F. The other record says it too: our assassin snail record carries Aquarium Source restricting its prey to other snails that are smaller than them, naming trumpet, rabbit, ivory and ramshorn snails.

Two sources on this record and one on that one, which makes it one of the best sourced refusals on this site.

Rabbit snail with Betta, one setting only: Our two sources contradict each other by name. Fish Laboratory lists bettas among the animals to avoid; Bantam names betta fish among its recommended tank mates.

Bantam is also the source this record declines on temperature, and our own betta record spans 72 to 86 °F, so the water allows what the sources argue about.

Rabbit snail with Ramshorn snail, one setting only: The bands meet at exactly one temperature: this record starts at 78 and our ramshorn snail record stops there. No source names the pairing either way, and both animals want the same hard alkaline water, so what rules it out is one degree of overlap rather than a warning.

Rabbit snail with Nerite snail, one setting only: Two degrees of shared band, and Aquarium Breeder names multiple snail species including nerites among the compatible tank mates for this one. So this is a recommendation the arithmetic almost refuses: our nerite snail record stops at 79 °F and this one starts at 78.

Ramshorn snail with Assassin snail, never: Named from both sides, which is as clear as a refusal gets here. Aquarium Source names the assassin snail among the predators of this species. Our own assassin snail record carries three sources naming ramshorn snails as prey: Aquarium Breeder lists bladder, ramshorn and Malaysian trumpet snails, Aquarium Source lists trumpet, rabbit, ivory and ramshorn, and AquaticMotiv lists bladder, pond and ramshorn.

The temperature bands overlap from 75 to 78 °F, so the water allows exactly what both records refuse.

Ramshorn snail with Pea puffer, never: Fishkeeping World names puffers among the animals that eat ramshorn snails. Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is the other half of the same sentence: a ramshorn at 18 to 25 mm is the small snail that instruction is about.

That record already refuses our nerite snail and is cautioned against our assassin snail, and this is the pairing its own diet row was written for.

Ramshorn snail with Honey gourami, one setting only: Fishkeeping World names gouramis among the animals that eat ramshorn snails. Not one of the four sources on our honey gourami record mentions snails at all, and three of them call that species peaceful.

So a source we cite warns about the family while the sources on our own record are silent about it, which is a caution rather than a refusal. Our gourami fish guide adds the mouth-size rule from a fourth source: a dwarf gourami will opportunistically snack on anything that can fit in its mouth.

Clown killifish with Cherry shrimp, one setting only: The most precise shrimp answer any source on this site has given. Aquarium Co-Op: clown killifish do not seem to eat adult dwarf shrimp, but baby shrimp are fair game.

Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so both halves of that sentence apply to the same tank at the same time. The water allows it: temperature meets from 68 to 79 and hardness from 71 to 143 ppm.

A colony survives and a generation does not, which is a caution rather than a refusal because our source says so in those terms.

Clown killifish with Betta, one setting only: Aquarium Co-Op names the betta as a tank mate whose compatibility depends on individual temperament, which is the only pairing it hedges. Our betta record carries one source that will not put a betta in a community tank at all against another naming five tank mates, so both records leave the same question open.

The water is the other half: that record prints around 80 °F and this one stops at 79, so the two published figures meet at nothing, and the tolerance range on the betta record, 72 to 86, is what the pairing would have to run on.

Clown killifish with Nerite snail, one setting only: Aquarium Co-Op names snails among the tank mates for this fish, and our own two records will not support it. Our nerite snail record carries pH 7.5 to 8.5 and this record carries 4.0 to 7.0, so the two ranges do not meet at all, and the hardness only meets if both are read at their extremes.

A snail needs carbonate and this fish is published for water with almost none, which is the same failure our platy record found from the opposite end of the pH scale.

Least killifish with Betta, never: Seriously Fish again, and here the fish is the right size to be food rather than the wrong size to be safe. Our betta record is 2.4 to 2.8 inches and runs 72 to 86 °F, containing this record’s whole band, so there is no setting that separates them.

Seriously Fish names the mates it would accept instead and three of them have records here: dwarf Corydoras, Otocinclus and freshwater shrimp, which on this site is our cherry shrimp, amano shrimp and ghost shrimp records.

Guppy with Ember tetra, one setting only: Ours, from the published pH rows rather than from anything either source says: the guppy floor is 7.0 and the ember tetra ceiling is 7.0, so the two records meet at one number and share no range at all. A tank held exactly at neutral suits both and any drift suits one.

Guppy with Kuhli loach, one setting only: Ours, from two rows this time. The pH ranges meet only at 7.0, and the hardness ranges meet only at 143 ppm, which is the guppy floor and the kuhli loach ceiling. Nothing either source says forbids the pairing; the arithmetic leaves it no room.

Honey gourami with Betta, one setting only: Ours, and a caution rather than a refusal because the disagreement sits on the other record. The water is not the problem: 74 to 81 here against 72 to 86 there, and both animals are anabantoids that breathe air and build bubble nests.

What makes the pairing a question is that our betta record carries one source saying never to keep a betta in a community tank against another that names five tank mates. Nothing on either record names the other animal, so the arithmetic allows it and the betta’s own sources have not settled whether it belongs in a community at all.

Pea puffer with Nerite snail, never: This is diet rather than temperament. Seriously Fish states the puffer needs small snails with the shell on regularly, and Aquarium Co-Op names live pest snails among what it eats. A nerite is a snail bought to live for one to two years, not a feeder.

Pea puffer with Otocinclus, one setting only: Ours, from a direct contradiction: Seriously Fish names Otocinclus spp. as compatible with this fish, and Aquarium Co-Op says no algae eaters at all. We take the stricter side and mark it a caution rather than a refusal, because one of the two sources recommends the pairing and we are not going to pretend it does not.

Pea puffer with Rabbit snail, never: The snail record names this fish. FishioHub lists puffers, large loaches and assassin snails as incompatible with rabbit snails, and this record already carries a source putting snails with the shell on in its own diet row. The bands overlap from 78 to 82 °F.

Pea puffer with Cherry shrimp, one setting only: Ours, and the same shape of problem. Seriously Fish allows some freshwater shrimp with this fish; Aquarium Co-Op says no clean up crew. Our own shrimp record adds the figure that decides it for us: the young hatch at about a millimeter, and this is a fish that eats snails out of their shells.

Platy with Bristlenose pleco, one setting only: Aquarium Co-Op names bristlenose plecos among the tank mates for a platy, and our own two records will not support it on water. This record carries 214 to 321 ppm and our bristlenose pleco record carries 71 to 200, so the hardness ranges do not meet at all.

The pH meets from 7.0 to 7.5 and the temperature from 74 to 77. A source we cite recommends a pairing our own hardness rows exclude, which is the same shape as the kuhli loach cell on our clown loach record.

Platy with Ember tetra, one setting only: Two problems at once. Our ember tetra record carries pH 5.5 to 7.0 against 7.0 to 8.0 here, so the two meet at a single point, and hardness 18 to 179 ppm against 214 to 321, which do not meet at all.

Fishkeeping World adds a warning from the other direction: long-finned platy varieties should not be kept with renowned fin-nippers such as tiger barbs and tetras. Our ember tetra record stores peaceful, shoaling from a source describing that species, so the family warning and the species statement point different ways, and the cell prints both.

Platy with Otocinclus, one setting only: Ours, from two published rows. Our otocinclus record carries 36 to 179 ppm against 214 to 321 here, so there is no shared hardness, while the pH meets from 7.0 to 7.5 and the temperature from 70 to 77.

No source on either record names the pairing. It is the same failure as the bristlenose cell and it is worth printing twice, because the reason this fish is hard to pair is one row that most keepers never test.

African dwarf frog with Cherry shrimp, never: Aquarium Breeder is unambiguous: African dwarf frogs will eat all your dwarf shrimp, it is simply inevitable. Our cherry shrimp record is a dwarf shrimp, and its own page is built around breeding a colony.

The same source gives amano and ghost shrimp a chance because they can grow up to 2 inches, which is the size of the frog itself.

Axolotl with Goldfish, never: These are the two records with the lowest temperature ceilings on this site and they do not meet. The axolotl band ends at 64 °F and the goldfish band starts at 68, so the coldest fish we hold is four degrees too warm for this animal.

Both are sold as beginner pets in the same shops, and both records carry a source warning that the usual advice will kill them.

Bristlenose pleco with Otocinclus, never: Both are sold as algae eaters and both records carry a source saying algae alone will not feed them. The otocinclus record has three of four sources asking for a heavily planted tank and 6 or more fish in a 10 gallon; this one has one fish, a cave, a 20 gallon and a source that says it may snack on sword plants. They solve the same problem in a tank of a different size.

German blue ram with Corydoras, one setting only: Two sources name corydoras as company, Aquarium Co-Op naming Sterbai cories specifically and Seriously Fish naming bottom-dwelling Corydoras on its Bolivian ram page. Our own corydoras record stops at 82 °F, two degrees below this row, so the recommendation and the arithmetic do not meet.

Amano shrimp with Goldfish, never: Named, not inferred. Aquarium Co-Op says to stay away from any fish big enough to eat them and gives three examples: medium to large cichlids, barbs, and goldfish.

We hold records for the goldfish and for two cichlids, the angelfish and the oscar, so one sentence in one source refuses three of our own records at once.

Assassin snail with Nerite snail, never: Named, and by the most detailed source on this record. Asked whether assassin snails eat mystery and nerite snails, Aquarium Breeder answers: eventually, yes, and it says larger snails are taken if the assassins gang up.

Aquarium Source restricts the prey to snails smaller than themselves, which a 0.5 to 1.5 inch nerite is not always, and AquaticMotiv puts bigger snails on the safe list. So one source refuses the pairing outright and two allow it with a size condition, and the record refuses it: our nerite snail record is the animal a keeper paid a premium for, and one source we cite says it goes eventually. It is the third refusal against that record, after the pea puffer and the clown loach.

Assassin snail with Cherry shrimp, one setting only: Every source that addresses shrimp says yes with a condition attached, and no two conditions match. Aquarium Breeder: yes, they do eat shrimp, but only the weak, the sick, or the ones that are molting.

Aquarium Source names shrimp fry among its foods. AquaticMotiv: only smaller or baby shrimp, while larger or adult shrimp are typically safe. Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so the adults sit on the safe side of all three conditions and every generation after them does not.

The cell is a caution because that is exactly what our sources describe: not a refusal, and not a pairing anybody should call safe either.

Assassin snail with Pea puffer, never: Named from both sides, which settles a cell the first draft of this record marked a caution. Aquarium Breeder lists pufferfish among the animals that will eat an assassin snail, alongside cichlids, loaches and goldfish.

Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is why that record already refuses our nerite snail. So one source says the puffer eats this snail and our own record says the puffer needs snails: the two statements are the same statement. The bands would have allowed it, since that record runs 74 to 82 °F against 75 to 80 here.

Assassin snail with Kuhli loach, one setting only: A group warning against a species statement, which our snails silo already argues about. AquaticMotiv names loaches among the tank mates to avoid for this snail.

Our kuhli loach record carries Aquarium Co-Op saying of that species, in as many words, that it is not known for eating snails. So one source warns about the family and another clears the member, and the cell prints the disagreement instead of picking a side. The water allows it: 74 to 79 °F there against 75 to 80 here, meeting from 75 to 79.

Cherry shrimp with Betta, never: Aquarium Co-Op states bettas are notorious for going after shrimp. Our record marks the pairing never rather than risky, and the reason is that the young hatch at about a millimeter.

Ghost shrimp with Betta, never: The same verdict as our cherry shrimp record and a different reason for it. No source on this record names the betta, but two of them state that ghost shrimp are bought as feeders for larger aggressive fish, and at 1 to 1.5 inches this animal is the same size as the shrimp our betta guide already refuses.

Rabbit snail with Assassin snail, never: Two sources name assassin snails among the animals to avoid with this one. Aquarium Breeder lists them alongside crayfish, cichlids, loaches and goldfish, and Fish Laboratory lists bettas, tiger barbs, cichlids, crayfish and assassin snails.

Our own assassin snail record carries a source saying it hunts snails and does not eat algae, and the bands overlap from 78 to 80 °F. The other record says it too: our assassin snail record carries Aquarium Source restricting its prey to other snails that are smaller than them, naming trumpet, rabbit, ivory and ramshorn snails.

Two sources on this record and one on that one, which makes it one of the best sourced refusals on this site.

Rabbit snail with Betta, one setting only: Our two sources contradict each other by name. Fish Laboratory lists bettas among the animals to avoid; Bantam names betta fish among its recommended tank mates.

Bantam is also the source this record declines on temperature, and our own betta record spans 72 to 86 °F, so the water allows what the sources argue about.

Rabbit snail with Ramshorn snail, one setting only: The bands meet at exactly one temperature: this record starts at 78 and our ramshorn snail record stops there. No source names the pairing either way, and both animals want the same hard alkaline water, so what rules it out is one degree of overlap rather than a warning.

Rabbit snail with Nerite snail, one setting only: Two degrees of shared band, and Aquarium Breeder names multiple snail species including nerites among the compatible tank mates for this one. So this is a recommendation the arithmetic almost refuses: our nerite snail record stops at 79 °F and this one starts at 78.

Ramshorn snail with Assassin snail, never: Named from both sides, which is as clear as a refusal gets here. Aquarium Source names the assassin snail among the predators of this species. Our own assassin snail record carries three sources naming ramshorn snails as prey: Aquarium Breeder lists bladder, ramshorn and Malaysian trumpet snails, Aquarium Source lists trumpet, rabbit, ivory and ramshorn, and AquaticMotiv lists bladder, pond and ramshorn.

The temperature bands overlap from 75 to 78 °F, so the water allows exactly what both records refuse.

Ramshorn snail with Kuhli loach, one setting only: The group warning against a species statement, which our snails silo has now argued three times. Fishkeeping World names loaches as animals that eat ramshorn snails.

Our kuhli loach record carries Aquarium Co-Op saying of that species, in as many words, that it is not known for eating snails. One source warns about the family and another clears the member, and the cell prints both rather than choosing. The bands meet from 74 to 78 °F.

Ramshorn snail with Pea puffer, never: Fishkeeping World names puffers among the animals that eat ramshorn snails. Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is the other half of the same sentence: a ramshorn at 18 to 25 mm is the small snail that instruction is about.

That record already refuses our nerite snail and is cautioned against our assassin snail, and this is the pairing its own diet row was written for.

Ramshorn snail with Honey gourami, one setting only: Fishkeeping World names gouramis among the animals that eat ramshorn snails. Not one of the four sources on our honey gourami record mentions snails at all, and three of them call that species peaceful.

So a source we cite warns about the family while the sources on our own record are silent about it, which is a caution rather than a refusal. Our gourami fish guide adds the mouth-size rule from a fourth source: a dwarf gourami will opportunistically snack on anything that can fit in its mouth.

Clown killifish with Cherry shrimp, one setting only: The most precise shrimp answer any source on this site has given. Aquarium Co-Op: clown killifish do not seem to eat adult dwarf shrimp, but baby shrimp are fair game.

Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so both halves of that sentence apply to the same tank at the same time. The water allows it: temperature meets from 68 to 79 and hardness from 71 to 143 ppm.

A colony survives and a generation does not, which is a caution rather than a refusal because our source says so in those terms.

Clown killifish with Betta, one setting only: Aquarium Co-Op names the betta as a tank mate whose compatibility depends on individual temperament, which is the only pairing it hedges. Our betta record carries one source that will not put a betta in a community tank at all against another naming five tank mates, so both records leave the same question open.

The water is the other half: that record prints around 80 °F and this one stops at 79, so the two published figures meet at nothing, and the tolerance range on the betta record, 72 to 86, is what the pairing would have to run on.

Clown killifish with Nerite snail, one setting only: Aquarium Co-Op names snails among the tank mates for this fish, and our own two records will not support it. Our nerite snail record carries pH 7.5 to 8.5 and this record carries 4.0 to 7.0, so the two ranges do not meet at all, and the hardness only meets if both are read at their extremes.

A snail needs carbonate and this fish is published for water with almost none, which is the same failure our platy record found from the opposite end of the pH scale.

Least killifish with Betta, never: Seriously Fish again, and here the fish is the right size to be food rather than the wrong size to be safe. Our betta record is 2.4 to 2.8 inches and runs 72 to 86 °F, containing this record’s whole band, so there is no setting that separates them.

Seriously Fish names the mates it would accept instead and three of them have records here: dwarf Corydoras, Otocinclus and freshwater shrimp, which on this site is our cherry shrimp, amano shrimp and ghost shrimp records.

Guppy with Ember tetra, one setting only: Ours, from the published pH rows rather than from anything either source says: the guppy floor is 7.0 and the ember tetra ceiling is 7.0, so the two records meet at one number and share no range at all. A tank held exactly at neutral suits both and any drift suits one.

Guppy with Kuhli loach, one setting only: Ours, from two rows this time. The pH ranges meet only at 7.0, and the hardness ranges meet only at 143 ppm, which is the guppy floor and the kuhli loach ceiling. Nothing either source says forbids the pairing; the arithmetic leaves it no room.

Honey gourami with Betta, one setting only: Ours, and a caution rather than a refusal because the disagreement sits on the other record. The water is not the problem: 74 to 81 here against 72 to 86 there, and both animals are anabantoids that breathe air and build bubble nests.

What makes the pairing a question is that our betta record carries one source saying never to keep a betta in a community tank against another that names five tank mates. Nothing on either record names the other animal, so the arithmetic allows it and the betta’s own sources have not settled whether it belongs in a community at all.

Pea puffer with Nerite snail, never: This is diet rather than temperament. Seriously Fish states the puffer needs small snails with the shell on regularly, and Aquarium Co-Op names live pest snails among what it eats. A nerite is a snail bought to live for one to two years, not a feeder.

Pea puffer with Otocinclus, one setting only: Ours, from a direct contradiction: Seriously Fish names Otocinclus spp. as compatible with this fish, and Aquarium Co-Op says no algae eaters at all. We take the stricter side and mark it a caution rather than a refusal, because one of the two sources recommends the pairing and we are not going to pretend it does not.

Pea puffer with Rabbit snail, never: The snail record names this fish. FishioHub lists puffers, large loaches and assassin snails as incompatible with rabbit snails, and this record already carries a source putting snails with the shell on in its own diet row. The bands overlap from 78 to 82 °F.

Pea puffer with Cherry shrimp, one setting only: Ours, and the same shape of problem. Seriously Fish allows some freshwater shrimp with this fish; Aquarium Co-Op says no clean up crew. Our own shrimp record adds the figure that decides it for us: the young hatch at about a millimeter, and this is a fish that eats snails out of their shells.

Platy with Bristlenose pleco, one setting only: Aquarium Co-Op names bristlenose plecos among the tank mates for a platy, and our own two records will not support it on water. This record carries 214 to 321 ppm and our bristlenose pleco record carries 71 to 200, so the hardness ranges do not meet at all.

The pH meets from 7.0 to 7.5 and the temperature from 74 to 77. A source we cite recommends a pairing our own hardness rows exclude, which is the same shape as the kuhli loach cell on our clown loach record.

Platy with Ember tetra, one setting only: Two problems at once. Our ember tetra record carries pH 5.5 to 7.0 against 7.0 to 8.0 here, so the two meet at a single point, and hardness 18 to 179 ppm against 214 to 321, which do not meet at all.

Fishkeeping World adds a warning from the other direction: long-finned platy varieties should not be kept with renowned fin-nippers such as tiger barbs and tetras. Our ember tetra record stores peaceful, shoaling from a source describing that species, so the family warning and the species statement point different ways, and the cell prints both.

Platy with Otocinclus, one setting only: Ours, from two published rows. Our otocinclus record carries 36 to 179 ppm against 214 to 321 here, so there is no shared hardness, while the pH meets from 7.0 to 7.5 and the temperature from 70 to 77.

No source on either record names the pairing. It is the same failure as the bristlenose cell and it is worth printing twice, because the reason this fish is hard to pair is one row that most keepers never test.

African dwarf frog with Cherry shrimp, never: Aquarium Breeder is unambiguous: African dwarf frogs will eat all your dwarf shrimp, it is simply inevitable. Our cherry shrimp record is a dwarf shrimp, and its own page is built around breeding a colony.

The same source gives amano and ghost shrimp a chance because they can grow up to 2 inches, which is the size of the frog itself.

Axolotl with Goldfish, never: These are the two records with the lowest temperature ceilings on this site and they do not meet. The axolotl band ends at 64 °F and the goldfish band starts at 68, so the coldest fish we hold is four degrees too warm for this animal.

Both are sold as beginner pets in the same shops, and both records carry a source warning that the usual advice will kill them.

Bristlenose pleco with Otocinclus, never: Both are sold as algae eaters and both records carry a source saying algae alone will not feed them. The otocinclus record has three of four sources asking for a heavily planted tank and 6 or more fish in a 10 gallon; this one has one fish, a cave, a 20 gallon and a source that says it may snack on sword plants. They solve the same problem in a tank of a different size.

German blue ram with Corydoras, one setting only: Two sources name corydoras as company, Aquarium Co-Op naming Sterbai cories specifically and Seriously Fish naming bottom-dwelling Corydoras on its Bolivian ram page. Our own corydoras record stops at 82 °F, two degrees below this row, so the recommendation and the arithmetic do not meet.

Amano shrimp with Goldfish, never: Named, not inferred. Aquarium Co-Op says to stay away from any fish big enough to eat them and gives three examples: medium to large cichlids, barbs, and goldfish.

We hold records for the goldfish and for two cichlids, the angelfish and the oscar, so one sentence in one source refuses three of our own records at once.

Assassin snail with Nerite snail, never: Named, and by the most detailed source on this record. Asked whether assassin snails eat mystery and nerite snails, Aquarium Breeder answers: eventually, yes, and it says larger snails are taken if the assassins gang up.

Aquarium Source restricts the prey to snails smaller than themselves, which a 0.5 to 1.5 inch nerite is not always, and AquaticMotiv puts bigger snails on the safe list. So one source refuses the pairing outright and two allow it with a size condition, and the record refuses it: our nerite snail record is the animal a keeper paid a premium for, and one source we cite says it goes eventually. It is the third refusal against that record, after the pea puffer and the clown loach.

Assassin snail with Cherry shrimp, one setting only: Every source that addresses shrimp says yes with a condition attached, and no two conditions match. Aquarium Breeder: yes, they do eat shrimp, but only the weak, the sick, or the ones that are molting.

Aquarium Source names shrimp fry among its foods. AquaticMotiv: only smaller or baby shrimp, while larger or adult shrimp are typically safe. Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so the adults sit on the safe side of all three conditions and every generation after them does not.

The cell is a caution because that is exactly what our sources describe: not a refusal, and not a pairing anybody should call safe either.

Assassin snail with Pea puffer, never: Named from both sides, which settles a cell the first draft of this record marked a caution. Aquarium Breeder lists pufferfish among the animals that will eat an assassin snail, alongside cichlids, loaches and goldfish.

Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is why that record already refuses our nerite snail. So one source says the puffer eats this snail and our own record says the puffer needs snails: the two statements are the same statement. The bands would have allowed it, since that record runs 74 to 82 °F against 75 to 80 here.

Assassin snail with Kuhli loach, one setting only: A group warning against a species statement, which our snails silo already argues about. AquaticMotiv names loaches among the tank mates to avoid for this snail.

Our kuhli loach record carries Aquarium Co-Op saying of that species, in as many words, that it is not known for eating snails. So one source warns about the family and another clears the member, and the cell prints the disagreement instead of picking a side. The water allows it: 74 to 79 °F there against 75 to 80 here, meeting from 75 to 79.

Cherry shrimp with Betta, never: Aquarium Co-Op states bettas are notorious for going after shrimp. Our record marks the pairing never rather than risky, and the reason is that the young hatch at about a millimeter.

Ghost shrimp with Betta, never: The same verdict as our cherry shrimp record and a different reason for it. No source on this record names the betta, but two of them state that ghost shrimp are bought as feeders for larger aggressive fish, and at 1 to 1.5 inches this animal is the same size as the shrimp our betta guide already refuses.

Rabbit snail with Assassin snail, never: Two sources name assassin snails among the animals to avoid with this one. Aquarium Breeder lists them alongside crayfish, cichlids, loaches and goldfish, and Fish Laboratory lists bettas, tiger barbs, cichlids, crayfish and assassin snails.

Our own assassin snail record carries a source saying it hunts snails and does not eat algae, and the bands overlap from 78 to 80 °F. The other record says it too: our assassin snail record carries Aquarium Source restricting its prey to other snails that are smaller than them, naming trumpet, rabbit, ivory and ramshorn snails.

Two sources on this record and one on that one, which makes it one of the best sourced refusals on this site.

Rabbit snail with Betta, one setting only: Our two sources contradict each other by name. Fish Laboratory lists bettas among the animals to avoid; Bantam names betta fish among its recommended tank mates.

Bantam is also the source this record declines on temperature, and our own betta record spans 72 to 86 °F, so the water allows what the sources argue about.

Rabbit snail with Ramshorn snail, one setting only: The bands meet at exactly one temperature: this record starts at 78 and our ramshorn snail record stops there. No source names the pairing either way, and both animals want the same hard alkaline water, so what rules it out is one degree of overlap rather than a warning.

Rabbit snail with Nerite snail, one setting only: Two degrees of shared band, and Aquarium Breeder names multiple snail species including nerites among the compatible tank mates for this one. So this is a recommendation the arithmetic almost refuses: our nerite snail record stops at 79 °F and this one starts at 78.

Ramshorn snail with Assassin snail, never: Named from both sides, which is as clear as a refusal gets here. Aquarium Source names the assassin snail among the predators of this species. Our own assassin snail record carries three sources naming ramshorn snails as prey: Aquarium Breeder lists bladder, ramshorn and Malaysian trumpet snails, Aquarium Source lists trumpet, rabbit, ivory and ramshorn, and AquaticMotiv lists bladder, pond and ramshorn.

The temperature bands overlap from 75 to 78 °F, so the water allows exactly what both records refuse.

Ramshorn snail with Kuhli loach, one setting only: The group warning against a species statement, which our snails silo has now argued three times. Fishkeeping World names loaches as animals that eat ramshorn snails.

Our kuhli loach record carries Aquarium Co-Op saying of that species, in as many words, that it is not known for eating snails. One source warns about the family and another clears the member, and the cell prints both rather than choosing. The bands meet from 74 to 78 °F.

Ramshorn snail with Pea puffer, never: Fishkeeping World names puffers among the animals that eat ramshorn snails. Our pea puffer record carries Seriously Fish asking for small snails with the shell on regularly, which is the other half of the same sentence: a ramshorn at 18 to 25 mm is the small snail that instruction is about.

That record already refuses our nerite snail and is cautioned against our assassin snail, and this is the pairing its own diet row was written for.

Ramshorn snail with Honey gourami, one setting only: Fishkeeping World names gouramis among the animals that eat ramshorn snails. Not one of the four sources on our honey gourami record mentions snails at all, and three of them call that species peaceful.

So a source we cite warns about the family while the sources on our own record are silent about it, which is a caution rather than a refusal. Our gourami fish guide adds the mouth-size rule from a fourth source: a dwarf gourami will opportunistically snack on anything that can fit in its mouth.