The betta fish tank mates list, with the reason for each
A list without reasons is a list you cannot apply to your own tank. Each verdict below carries the reason it holds, so you can tell whether it holds for you.
Three conditions the whole answer rests on
Every verdict above assumes all three. Remove one and the honest answer becomes keep the betta alone.
Ten to twenty gallons
Company needs somewhere to be that is not where the betta is. In five gallons there is no such place, and that is the whole reason the answer changes.
Real cover, not decoration
Plants, driftwood and shade let the betta claim a territory and let everything else stay out of it. A bare tank has no out of the way.
A way to separate them
Individual temper varies enough that no source promises more than usually fine. A spare tank or a divider is the difference between a plan and a hope.
Two tanks that actually work
Counts taken from each species' own record, not from a rule about inches per gallon. One species per layer, and the betta keeps the surface.
- Betta1
- Ember tetra6 to 10
- Betta1
- Harlequin rasbora6+
- Kuhli loach3 to 6
- Betta1
Where our sources disagree
This page would be dishonest without printing both positions, because the disagreement is the actual state of the knowledge.
Seriously Fish
Not recommended for the standard community aquarium. Best maintained alone, and species with trailing fins should be avoided.
Aquarium Co-Op
In ten to twenty gallons with cover, quiet company works: ember tetras, harlequin rasboras, corydoras, kuhli loaches, trumpet snails.
Reading the first week
Aggression has a vocabulary, and most of it happens at the surface. This is what each behavior means and what it asks you to do, in order of how much it should worry you.
| Behavior | What it means | What to do | Level |
|---|---|---|---|
| Flaring at glass | The betta sees its own reflection, usually against a dark background at night. | Move the light or the tank, not the fish. | Normal |
| A bubble raft | A healthy male doing what the species does at the surface. | Nothing. | Normal |
| Patrolling the top | Territory held, company keeping to the middle and the floor. This is the arrangement working. | Keep watching for a week. | Normal |
| Short chases | Boundary setting, and it stops when the other fish leaves the surface. | Add cover so the chase has an exit. | Watch |
| Chases at the water line | The other fish has nowhere to go. This is the signal in the separation plan. | Divide the tank today, decide tomorrow. | Act |
| Nipped fins on the company | Damage has already happened, so the pairing has failed for this individual. | Move the company out and do not retry it. | Failed |
The first fourteen days
Set the tank around the betta
Cover at the back, an open swimming lane at the front, a calm surface and the heater holding its number. The company moves into a finished tank, not into a building site.
Add the school, not the betta
Where you can choose the order, the schooling fish go in first and get a few days to claim the middle. A betta added later has less to defend because the territory was never only his.
Watch the surface at feeding time
Food is when the boundaries get tested. Feed at the surface for the betta and drop something sinking for the others, so the two groups are not eating in the same place.
Count fins, not fish
Everyone present is not the same as everyone intact. Ragged edges on the company are the earliest honest sign, and they show before you ever see a chase.
Decide, then stop watching
If two weeks have passed with no chasing at the water line and no damage, this pairing works with this individual. Keep the divider anyway: temperament can change with age, and nothing in either source promises otherwise.
The question we will not answer
Can a betta live with shrimp?
This is the most asked question on this topic and we print no verdict, because the two sources this guide was built from state none, and the source that has turned up since contradicts our own cherry shrimp record rather than settling it. Here is everything we do have, so you can make the call with the same information we have:
- One source describes bettas as notorious for going after shrimp, in a guide about tank mates rather than in a care record.
- The betta record states the species is a carnivore that hunts small aquatic invertebrates in nature. A cherry shrimp is a small aquatic invertebrate.
- The cherry shrimp record states an adult size of 1.5 inches and gives the rule keepers use: if it fits in the fish's mouth, that fish is a predator.
- What none of them states: a tank size, a plant density, or a shrimp colony size at which this becomes reliably safe. That is still true of every source read since, including the one that calls dwarf shrimp safe, and it is the number we would have to invent, so we do not.
If you try it, treat the shrimp as livestock you may lose and give the colony more cover than you think it needs. When we find a source willing to state a threshold, this section becomes a verdict.
The records behind the verdicts
Each species that clears has its own record, with its own group size and its own blanks. The verdict on this page is only as good as those.
When it goes wrong
The separation plan, before you need it
Aggression usually shows in the first week and almost always at the surface. Decide these five things while nothing is happening, because the moment it starts you will be improvising with a net.
- Watch the surface, not the fish. Chasing that ends at the water line is the signal. Fin nipping that leaves marks is already late.
- Know which one moves. The betta stays, the company goes, because the tank was set up around the betta's territory.
- Keep a second box cycled. A five gallon with a heater and a filter you already run is the whole plan. A bucket is not.
- Divide before you rehome. A tank divider buys a week to decide instead of an hour.
- Do not retry the same pairing. If it failed once with this individual, it is that individual, and the record cannot help you further.
The two questions this guide declined, and what a source says now
This guide has a station above headed the question we will not answer, and it named two: shrimp compatibility and female groups. Neither of the two sources it was built from stated a position. Both have one now, from sources read since, and neither answer is comfortable.
Shrimp: not a blank any more, a contradiction
Aqueon names dwarf freshwater shrimp among safe betta fish tank mates, alongside mystery snails and live aquatic plants. Our cherry shrimp record marks the same pairing never, because Aquarium Co-Op describes bettas as notorious for going after shrimp and Wikipedia records that the young hatch at about a millimeter.
- Both are right about different animals. An adult cherry shrimp at 30 to 40 mm is not obvious food. A one millimeter juvenile is.
- Which is why the record says what it says. A colony is kept successfully in heavily planted tanks, and what makes it work is losses you never count.
- So the verdict stays never, and the reason it stays is now printed rather than implied: this site refuses a pairing that ends a breeding colony even when the adults survive it.
- If you want the shrimp as a cleanup crew rather than a colony, one source supports you and one does not, and the disagreement is the honest answer.
Female groups: three sources, two floors, one gap
Aqueon states that female bettas can live together in a small school known as a sorority. PetMD asks for at least 10 gallons and lots of hiding places. Fishkeeping World says groups of five or more.
So a sorority has a floor on both axes and this guide can now print it: five or more animals, ten gallons or more, and cover. What none of the three addresses is two or three females together, which is the arrangement most people actually try, and that part of the blank stays exactly as blank as it was.
The tank size figure nothing else here holds
Aqueon states that if a betta will share space with other fish, snails or growing plants, you need an aquarium that is 27 gallons or larger. Our betta record holds 5 to 10 gallons for a single fish, and the stocking calculator supports a betta plus one group at ten.
That is a gap of nearly three times on the one number a reader of this guide most needs. We are not going to average it. What the two positions have in common is the direction every source here takes: a betta alone is a small tank question and a betta with company is a bigger tank question than the community fish would need on their own.
One thing that corroborates rather than conflicts
Aqueon calls the corydoras catfish a chill bottom feeder and says they like to live in groups, so plan to get five or more. Our corydoras record asks for six or more of one species. Two sources arriving at the same floor from opposite directions, and this guide already clears the pairing.
Questions keepers actually ask about betta fish tank mates
Can a betta live with shrimp?
Neither of our sources records shrimp as a betta tank mate, so we print no verdict. What one of them does record is that bettas are notorious for going after shrimp, and that a betta is a carnivore which hunts small invertebrates in nature. Read that as a risk, not as a ban we can source.
Will a betta kill a snail?
It can pick at one. The difference between the two snails above is daylight: trumpet snails burrow while the betta is awake, and a mystery snail waves an antenna that looks like food.
How many tank mates can I add to a 10 gallon?
One school, not two. Six ember tetras or six harlequin rasboras, or a group of corydoras on the floor. Two schools plus a betta in ten gallons is where the water quality story starts.
Can two female bettas live together?
Not recorded. Our sources state that males cannot cohabit and do not give us a verified position on groups of females, so we do not print one.
My betta ignores everyone. Is it fine now?
Usually, and keep the separation plan anyway. Individual temper is the one variable no record can hold, which is exactly why the third condition exists.
Should I add the betta first or last?
Last, where you can choose. A school that has already claimed the middle gives the betta less to take, and it gives you a week of watching a settled tank rather than two new groups at once.
Does a bigger tank make a betta less aggressive?
It gives everyone else somewhere to be, which is not the same thing. The species trait does not change; the number of escape routes does, and that is what the ten to twenty gallon condition is buying.
Can I keep a betta with a pleco or an otocinclus?
Neither is recorded here yet, so we print no verdict. What the conditions above say still applies: a bottom dweller in a different layer, in ten gallons or more, with cover.
How long until I know it worked?
Two weeks with no chasing at the water line and no damage to fins. That is the window in the timeline above, and it is also when most keepers stop watching too early.
Do tank mates make a betta less lonely?
Nothing in either source supports that framing. A betta is territorial rather than social, so company is something the tank tolerates, not something the fish needs.
Every verdict above comes out of the betta care record: the layer it holds, the tank it needs, and the fields we have not verified.
- Tank
- 5 to 10 gal
- Temp
- 80 °F
- Layer
- Surface
- Blanks
- 2 fields
How this page was compiled
- By
- Verified
- Sources
Aquarium Co-Op tank mates guide, Seriously Fish, Aqueon, what fish can live with bettas, PetMD and Fishkeeping World
- Conflicts
Printed above rather than resolved quietly
- Not recorded
Two or three females together, which no source we hold addresses. Shrimp compatibility and female sororities were on this list until sources were found for both; the shrimp answer turned out to be a contradiction rather than a figure, and it is printed as one.