The thinnest topic on this site, and the one freshwater fish keepers ask about most
This is the honest state of it: of the forty eight records written, three state a lifespan and three carry real reproductive figures. The other six state no brood size, no gestation, no trigger, no fry food and no sexing method, because no source we compile from states them for those animals.
That is an unusual thing for a page to open with, and it is the reason this page exists in this form. Breeding is the subject where bad information is easiest to publish and hardest to check: the numbers are specific, they sound authoritative, and almost nobody who repeats them has counted anything. A page that filled these gaps would look far more finished than the site’s records deserve.
What we hold, and what we do not
The three fields nearest to breeding, printed for every record. Read the blanks as the subject of this page rather than as an oversight.
| Field | African dwarf frog | Amano shrimp | Angelfish | Assassin snail | Axolotl | Betta | Black molly | Bristlenose pleco | Celestial pearl danio | Cherry shrimp | Chili rasbora | Chinese algae eater | Clown killifish | Clown loach | Common pleco | Corydoras | Damselfish | Discus | Dojo loach | Ember tetra | Flowerhorn | German blue ram | Ghost shrimp | Goldfish | Guppy | Honey gourami | Kuhli loach | Least killifish | Mandarin goby | Nerite snail | Oscar fish | Otocinclus | Pea puffer | Platy | Rabbit snail | Ramshorn snail | Redtail catfish | Siamese algae eater | Sparkling gourami | Vampire shrimp |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lifespan | 5 to 8 years | 2 to 3 years | 8 to 12 years | 2 to 5 years | 10 to 20 years | 3 to 4 years | 3 to 5 years | 5 to 14 years | 3 to 5 years | 1 to 2 years | 4 to 8 years | 5 to 10 years | 2 to 5 years | 10 to 30 years | 10 to 15 years | Over 20 years, captive | 5 to 6 years | 10 to 15 years | 7 to 10 years | 2 to 4 years | 10 to 12 years | 2 to 4 years | Days to 1.5 years | 5 to 30 years | 2 to 3 years | 2 to 5 years | Up to 10 years | Up to 1.5 years, on one source | 2 to 4 years | 1 to 2 years | 10 to 20 years | not recorded | 2 to 6 years | 1 to 5 years | 2 to 3 years | 1 to 2 years | 15 to 20 years | 8 to 10 years | 4 to 5 years | 3 to 5 years |
| Growth rate | Mature at about 9 months | not recorded | not recorded | not recorded | Legs by 2 to 3 in, mature at 18 to 27 months | not recorded | not recorded | not recorded | Full size in 6 to 12 months | Mature at about two months | not recorded | not recorded | not recorded | Slow. About 6 in at three years | Can double in size in under 6 months | Juveniles look like small adults in about a month | not recorded | not recorded | Fast to 5 in, then about an inch a year | not recorded | Mature at 8 to 10 months, hump after a year | not recorded | Young are tank safe at about 5 weeks | Six inches in three to five months, if fed heavily | not recorded | not recorded | Mature at 2.75 in of a 4 in maximum | not recorded | not recorded | not recorded | Two thirds of adult size in 6 to 12 months | not recorded | not recorded | not recorded | About a year to 1.5 in | not recorded | 30 to 40 cm in the first year | Full size in about two years | not recorded | not recorded |
| Adult size | 1 to 3 in | 1 to 2 in | 4 to 6 in long, 6 to 8 in tall | 1 to 1.2 in (25 to 30 mm) | 9 to 12 in | 2.4 to 2.8 in (60 to 70 mm) | 3.1 to 4.5 in | 4 to 6 in | 0.8 to 1.5 in | 1.2 to 1.6 in (30 to 40 mm) | 0.7 to 0.8 in (18 to 20 mm) | 5 to 11 in (13 to 28 cm) | 1.4 in (35 mm) | 6 to 13 in in a tank (16 in recorded) | 15 in in a tank, 24 in the wild | 1 to 3 in | 3 in, and 12 for the largest in the family | 5 to 7 in | 6 to 12 in (15 to 30 cm) | 0.6 to 0.8 in (15 to 20 mm) | 9.5 to 16 in | 1.3 to 2.5 in (34 to 64 mm) | 1 to 1.5 in | 4 to 12 in | 2 to 2.5 in (50 to 64 mm) | 1.6 to 2.2 in (40 to 55 mm) | 3.5 to 3.9 in (90 to 100 mm) | 0.6 to 0.8 in male, 1 to 1.5 in female | 2.4 to 3 in | 0.5 to 1.5 in (13 to 38 mm) | 10 to 12 in, captive | 1.4 to 2 in (35 to 50 mm) | 1 in (25 mm) | 2 to 2.8 in (5 to 7 cm) | 2 to 4 in (5 to 10 cm) | 0.7 to 1 in (18 to 25 mm) | 47 to 55 in (120 to 140 cm) | 3 to 6.3 in | 1.5 to 1.6 in (40 mm) | 2 to 4.5 in, and 6 in the wild |
Lifespan matters here because a breeding plan is a timetable, and a species whose lifespan nobody publishes cannot be given one. Adult size matters because it is the closest thing our records hold to a size at maturity, and for the two animals on this site that reproduce readily in a tank it is the field the young are measured against.
Why each blank is blank
Every record stores the reason a field is empty, and on this topic those notes are the most useful thing we can print. They are the sentences a reader cannot get from a care sheet, because a care sheet does not admit to gaps.
Blank. No source states how fast an amano shrimp grows or when it is adult. Two publish figures that are often mistaken for it: Aquarium Care Basics gives a molt every five or six weeks, give or take, and Shrimpy Business gives six weeks for a female to carry eggs. Neither is a growth rate. Aquatic Arts gives the only figure adjacent to one, and it is a shipping figure: it ships young adults of half an inch to an inch.
Blank. Six sources and not one of them states how fast an angelfish grows or at what age it is adult. Aquarium Co-Op comes closest with figures for the other end of the life cycle: eggs hatch in two to three days and the fry become free swimming three to four days after that. The advice that depends on growth is published without it: buy at least six juveniles and raise them to adulthood, with no statement of how long that takes.
No source publishes a rate, a size at an age or a maturity date. The nearest anybody comes is the hatching time in station 08, and that is the figure our sources disagree about most.
Not stated by any of the four. Fishkeeping World gives an adult size of 2 to 3 in and adds that the better you care for the fish the larger and more vibrant it becomes, which is a direction rather than a rate. Seriously Fish, Aquarium Co-Op and PetMD state no growth figure at all. It is the last blank on this record, on the most searched animal on this site.
Not stated by Seriously Fish, Wikipedia, Aquarium Store Depot or Fishkeeping World. The nearest thing to a figure is Fishkeeping World on the fry, which are fed powdered flake until they can eat what the adults eat, at around two months old. That is a feeding milestone rather than a growth rate, so it stays out of the row and is recorded here. Our guppy, platy and least killifish records leave the same row blank, so no livebearer on this site carries one.
No source on this record publishes a growth rate, which is the ninth field and stays blank. The closest anybody comes is a pair of endpoints rather than a rate: Advanced Aquarium Concepts says they are sold as small as 1 to 1.5 inches and WebMD says juveniles in pet stores might only be about two inches long, against an adult 4 to 6 inches. Nobody says how long that takes.
No source publishes a rate. What Aquarium Co-Op gives instead is a warning about what a young one looks like in a shop: juvenile chili rasboras are not very colorful at first, but with good care and patience, they will one day look as red as rubies. It also notes that they will temporarily become paler whenever they move from one tank to another, and to give them a couple of weeks to adjust. Neither is a growth figure and both are more useful than one.
Not published by any of our six sources. The nearest thing to a rate is the disagreement in the size row, where one source says the fish will more than likely reach about 5 inches in an aquarium against a published maximum of 11, and none of them says how long either takes. The field stays blank.
No source publishes a rate, a size at an age or a maturity date. The only timescale on the record is the incubation period in station 08, and for once our sources agree on it.
Not stated by any of the four, which is what a record covering a family has to expect. Fishkeeping World publishes an adult size type by type, 3 in for the blue damselfish and 5 for the domino, and no rate for any of them. The closest figure anywhere is Wikipedia on Pomacentridae, where larvae are 2 to 4 mm and the pelagic stage lasts from under a week to more than a month. That measures the open ocean rather than a tank, so it is recorded here and not in the row.
No source publishes a rate, and two say something more useful about growth than a number would be. Aquarium Science: the ultimate size they reach is determined by how they are raised, and the larger the competitive discus, the more likely it is to win awards. aqua-fish warns about what that means in a shop, that juveniles with unusually intense coloration may have been hormone-treated or are stunted. Aquarium Co-Op notes only that discus take longer to reach full adult size compared to other cheaper fish like guppies. Wikipedia's one year to sexual maturity is the closest thing to a timescale anybody gives.
Not stated by any of the four. Aquarium Co-Op gives the adult size of up to 0.8 in, Aquarium Source writes about test kits and water changes instead, and neither Seriously Fish nor Shrimpy Business puts a figure on growth at all. On a fish that finishes at four fifths of an inch there may be very little to state, but that is a guess, and the row stays empty rather than carrying one.
Not published by any of our six sources. The closest is Aquarium Source, which says they are sexually mature at a very young age and after about six months they are ready to breed, and that is a maturity figure rather than a rate. The field stays blank.
Neither source states a rate. Aquarium Co-Op states the direction, that 82 °F increases growth and breeding, and attaches the cost in lifespan rather than a figure for the growth itself. Still no rate from any of the four. What arrived instead is a brood size and a gestation: Aquarium Source states upwards of 200 fry at once after 21 to 40 days.
No source publishes a rate or a developmental stage. The nearest anybody comes is aqua-fish giving the fry as free-swimming after about 3 days, which is a hatching timetable rather than a growth figure.
Not stated by Seriously Fish, Wikipedia, Aquarium Co-Op, Aquarium Store Depot or Aquariadise. The Aquarium Co-Op page is a livebearer roundup and the sizes printed near this entry belong to platies and goodeids rather than to this fish, which is the trap a roundup source sets on a record like this one. Aquarium Breeder is the sixth source here and its page will not serve a scripted request.
Not stated by any of the three. Fishkeeping World gives an adult size of up to 3 in and a lifespan of three to four years and nothing between them, Aquarium Store Depot writes about feeding and pod culture instead, and Wikipedia covers the species without a growth figure anywhere. It is the same gap our damselfish record carries, and on both marine records it is the only row left empty.
Not stated by any source we name. None of the three gives a growth figure or an age at maturity, and for an animal that cannot complete its life cycle in fresh water there may be nothing in a tank to measure.
Not stated by any of our four sources: neither Seriously Fish species profile, nor Aquarium Co-Op, nor Flip Aquatics, nor Splashy Fish. Left blank on purpose. This is a fish that often dies in its first month from starvation rather than from age, so a figure taken from tanks would be measuring the supply chain.
Not stated by either source, on the genus guide or on the two species profiles.
Not stated by either source. Seriously Fish gives a hatch time of about five days and a fry feeding order, which is a rearing schedule rather than a growth rate.
No source publishes a growth rate or a size at an age. What two of them publish instead is a feeding schedule for juveniles, two to three small meals a day per Aquarium Co-Op, which is a growth instruction without a growth figure.
No source publishes a rate or an age at a size. What two of them publish instead is a hatching time, and they disagree by a month: station 05 prints both.
Not stated by Seriously Fish, Wikipedia, Aquarium Source or Shrimpy Business. Aquarium Source comes closest with an adult size of about one and a half inches when fully grown, which is a size and not a rate, and Seriously Fish describes sexually mature individuals without attaching an age to them. Fish Laboratory is the fifth source here and its page returned no readable text for this check.
Neither Aquarium Store Depot nor Aquarium Care Basics states a rate: both give an adult size and a lifespan and nothing between them. Aquarium Breeder is the third source on this record and its page will not serve a scripted request, so this blank is recorded against the two that can be read rather than against all three. Our ghost shrimp and cherry shrimp records are the only two shrimp here that carry a figure on this row.
Two of those notes name the same thing in different words: a figure exists in circulation and has no source behind it. A lifespan for a betta is one of the most repeated numbers in the hobby, and for months neither source we held for that record stated one. The blank stayed, with the reason on it, until two care guides that are not forums published a figure. That is what a blank is for: not a gap to be filled with the loudest number, but a slot waiting for a source.
The two animals we can say something about
Cherry shrimp
Wikipedia states that the species matures at about two months, and that the young hatch as miniature adults with no larval stage. Those two facts together are most of why this animal breeds in an ordinary tank when almost nothing else on this site does: there is no separate rearing problem to solve, because there is no separate larval form to feed.
The record also holds the requirement behind it. Shrimp Science publishes GH 4 to 10, and Aquarium Co-Op names crushed coral for a continuously molting animal. A colony grows by building shells, so the mineral figure is the breeding figure whether or not anyone labels it one. Wikipedia adds the counts: 20 to 30 eggs at a time, taking two to three weeks to hatch, and young about a millimeter long. That last figure is the reason our records refuse the betta and cherry shrimp pairing outright.
Guppy
A livebearer, and the only record here with a full set of figures on it. Seriously Fish gives between 5 and 100 young from a single female, a gestation of four to six weeks, and the line that changes what you buy: a female can produce young for six months or more after a single mating. Aquarium Co-Op gives births approximately every thirty days.
It is also the only record here where a source prices the breeding. The same page states that 82 °F increases growth and breeding and cuts the lifespan to eighteen months, and that 72 °F slows development and pushes it beyond three and a half years.
Snail eggs, the largest question here
By search demand, snails are not a corner of this topic, they are most of it. Snail eggs on its own is the most searched question on our breeding list by a factor of nearly three over the next one, and the follow ups are specific: mystery snail eggs, nerite snail eggs, bladder snail eggs, ramshorn snail eggs. People are looking at a clutch on the glass and want to know what it is and what happens next.
Our one snail record now answers part of it, and the part it answers is the useful half. Four sources agree that the nerite cannot reproduce in fresh water: Shrimp Science states the young require a brief period of brackish conditions, Aquarium Co-Op states the eggs need brackish or salt water to reliably hatch, and Wikipedia describes an animal that returns to brackish water to breed. So the white specks are eggs, and nothing will come of them.
Where the eggs are laid, on driftwood and in the substrate. What they look like, hard white sesame seeds with dozens of eggs inside. And whether they hatch, which is no. Read it on the nerite snail record, with the source beside each line.
Every other snail. Bladder, ramshorn and trumpet snails all reproduce in the tank, which is the opposite situation and a different page, and we hold no record on any of them. Nothing we have says how long a nerite clutch stays on the glass either.
Questions about breeding aquarium fish
Which species on this site will breed in an ordinary tank?
Two of them. The cherry shrimp, where Wikipedia states maturity at about two months and young that hatch as miniature adults. And the guppy, which is a livebearer: Seriously Fish gives 5 to 100 young from a single female, a gestation of four to six weeks, and young produced for six months or more after one mating. Neither has a rearing stage you have to solve.
How long do these species live?
The cherry shrimp is one to two years, from two sources independently, and the nerite snail is about one to two years from Aquarium Co-Op. The corydoras record carries over twenty years in captivity from one source, and the pea puffer two to six from two. Only the otocinclus record is blank now, and it is blank against four sources rather than two. The betta reads 3 to 4 years, the ember tetra 2 to 4 and the kuhli loach up to ten, all three from sources found after those records were written.
Why did the betta record have no lifespan?
For a long time because neither of the two sources it was built from stated one, and a betta lifespan is a number you find repeated everywhere without an origin. Printing it would have made this database indistinguishable from the pages it exists to replace.
It now reads 3 to 4 years, the overlap of two sources that do state one: PetMD gives 3 to 5 with proper care and Fishkeeping World an average of 2 to 4. Neither is a forum. That is the process working rather than the rule bending.
What are the white specks on my aquarium glass?
If they are hard, white and about the size of a sesame seed, our nerite record says they are nerite eggs, laid on driftwood and in the substrate, and that they will not hatch in fresh water. If they are soft, clear or jelly like, we have no record that covers them: the snails that lay those do breed in fresh water and none of them is written here yet.
Do you publish breeding triggers?
One, and it comes with a price. Aquarium Co-Op states that 82 °F increases growth and breeding in guppies, and in the same paragraph that it cuts the lifespan to eighteen months. For our other forty eight records no source states a trigger at all, and without a figure a trigger is folklore with a mechanism bolted on.
Can I raise fry in the same tank?
For the cherry shrimp the question does not arise in the same way: the young are miniature adults grazing the same surfaces from the day they hatch, two to three weeks after a female carries 20 to 30 eggs. Guppy fry are free swimming from birth, and Aquarium Co-Op gives them three to five feedings a day against once or twice for adults. For every other animal on this site we hold nothing on fry at all.
How do I sex these species?
Two records describe it. Seriously Fish gives guppy males with elongated finnage and a gonopodium, and females larger, plumper and duller. For the pea puffer both our sources describe it: males deeper in color with a line or dot along the belly, females rounder with a yellow belly. The shrimp entry asks for one male and one female without saying how you would know, and the betta entry states one male and never two.
Does hardness affect breeding?
For the cherry shrimp our source publishes GH 4 to 10 as a requirement, and a growing colony is continuously building shells out of those minerals. That is the closest thing to a breeding parameter on this site, and it is on the hardness row rather than a breeding row.
Why is this topic so much emptier than the others?
Because the sources that publish careful water parameters mostly do not publish careful breeding figures, and the pages that do publish breeding figures rarely say where they came from. Our water and health topic can print three fields for every record; this one can print one field for one record.
What has to happen before this topic fills up?
Records that carry the fields. The guppy record shows what that looks like for a fish: a brood size, a gestation, a sexing method and a temperature effect, all from named sources. Two records now have enough on them to hold a guide up, which is two more than a month ago.
The guide this topic holds
One so far, and it is the one every fry keeper needs before any of the others.
What is not here yet
One guide is filed under this topic and it is not about a fish. Brine shrimp are what you hatch the week after the fry arrive, and it is the largest single search term in our whole keyword map. The guides about the animals doing the spawning will probably still be the last of the five topics to fill. The demand is concentrated rather than spread: snail clutches, live bearing fish, and egg identification. The first of those three now has one record behind it. The other two need a species record with reproduction fields on it before a guide can be written from anything but memory.
When those fields arrive they appear in the table above the same day, and the blanks list below it gets shorter by exactly as much. Nothing on this page is written in a way that has to be edited when that happens.
Fry, and the two numbers this site now holds
This topic was written when no record here carried a brood size. One does now. The guppy record gained two figures from a source read this week, and they are the first fry numbers anywhere on this site.
- Upwards of 200 babies at once, per Aquarium Source. That is a brood, not a season.
- A gestation of 21 to 40 days. The same source, and the widest of the two figures.
- The adults will eat the fry alongside any other community fish. Also stated rather than inferred, which is rare on this subject.
- How often a female gives birth is not stated by any source we hold, so the arithmetic stops at one brood. A number for that exists everywhere and has no source behind it, which is the whole subject of the station above.
PetMD adds the part that makes the brood size matter: mixed sex groups often result in frequent reproduction and multiple generations. So the number that reaches adulthood in a community aquarium is nothing like two hundred, and the difference between the two figures is a second tank.
Two things about the tank rather than the species
Build Your Aquarium states that fish fry need to eat often when they are very young, five or six feedings per day at minimum, on infusoria, baby brine shrimp or tiny food particles. No record here holds a feeding frequency for an adult, let alone a fry, so that figure lives on this topic and nowhere else.
It also states that eggs and tiny fry get sucked into hang on back filters. That is the only equipment warning anywhere in this reading that is specific enough to act on, and it is the reason a breeding tank is usually described with a sponge filter instead.
Why livebearers keep coming first
Build Your Aquarium puts livebearers at the top for a reason it states plainly: they tend to mate more readily and with less outside manipulation than egg layers, and fry from livebearing parents often have a better chance of survival than the delicate eggs an egg layer produces. Of the records on this site the guppy is the livebearer, which is why it is the only one with a brood size.
The same page is candid about the parents. Platys, it says, can and probably will eat their own young; rosy barbs cannot be trusted not to; rosy red minnows may need removing from the hatchlings. None of those three is a record here, and the pattern is what matters: on this subject the danger to the young is usually their own parents rather than a tank mate.