The best betta tank mates
Organized by the volume each one needs, because that is the variable that decides it. Two of these work at five gallons and the rest do not.
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Read the threshold first
| Rated volume | Actual water | What can go in with a betta |
|---|---|---|
| Under 5 gal | 2.6 gal at 3 gal rated | Nothing. The tank is below our floor for the betta alone. |
| 5 gal | 4.3 gal | Invertebrates only - a nerite snail, or two or three Amano shrimp, with dense cover. No fish. |
| 10 gal | 8.5 gal | Fish become possible. A small bottom-dwelling group, or a modest mid-water shoal. Possible, not guaranteed. |
| 20 gal and up | 17 gal | A community tank that contains a betta - a different and much easier proposition. |
The list below is arranged by the volume each animal needs, not by how appealing it is. If your tank is five gallons, the list ends after the first two entries, and that is not a technicality.
Works at five gallons
Nerite snail
Needs: 5 gallons and up. One is plenty. A hard-shelled algae grazer that a betta cannot meaningfully hurt and generally ignores. It will not breed in fresh water - the larvae need brackish - so a nerite population cannot run away from you the way a bladder or ramshorn population will.
The catch is that it lays hard white eggs on hardscape and glass which do not hatch and are irritating to scrape off. That is the entire downside. The longer version.
Amano shrimp
Needs: 5 gallons and up, with dense cover. Two or three. Larger than cherry shrimp, which is exactly why they work - an adult Amano is big enough that most bettas leave it alone. They are excellent algae eaters and genuinely interesting to watch.
They also cannot breed in fresh water, which means no shrimplets and no population dynamics to manage. The requirement is cover: moss, a planted piece of wood, somewhere to be when the betta takes an interest. The longer version.
Works at ten gallons and up
A small bottom-dwelling group
Needs: 10 gallons minimum, and a group. Bottom-dwellers work with bettas because they occupy a part of the tank the betta does not defend. The constraint people ignore is that almost all of them are social and need a group of six or more - which is a bioload question as much as a welfare one, and it is why they do not fit in a five-gallon.
They also need substrate they will not damage themselves on: sand or smooth fine gravel, never sharp aquarium gravel.
A modest mid-water shoal
Needs: 10 gallons minimum, ideally more. Small, plain, fast fish that shoal tightly. Plain matters: a betta responds to bright color and trailing fins as though they belonged to a rival. Fast matters because it is the only defense available.
Six is the minimum for most shoaling species, which at ten gallons is close to your entire remaining bioload once the betta is accounted for.
Cherry shrimp: the honest version
Needs: 5 gallons and up, dense cover, and a decision. Cherry shrimp breed readily in fresh water. In a betta tank that means a continuous supply of shrimplets, most of which will be eaten. Some keepers regard that as a working system: the colony out-breeds the predation and both animals live normally. Others find it upsetting.
Both reactions are reasonable and you should decide which one is yours before buying, not afterwards. If you want shrimp you will actually watch grow, put them in their own tank - a 2.6 or 5-gallon is ideal - and keep the betta separate.
The popular recommendations that are wrong
| Commonly suggested | Why it does not work |
|---|---|
| One or two corydoras in a 5-gallon | Social species that need a group of six; a pair is a stressed pair, and a group of six does not fit in five gallons. |
| A single otocinclus | Also social, and a specialist feeder that starves in a tank without established algae. Frequently sold as a five-gallon algae solution. |
| Three neon tetras | A shoal of three is a stressed shoal. Six is the floor, which needs ten gallons or more. |
| Male guppies | Long-finned, brightly colored and slow - they read as rival bettas. The full comparison. |
| An african dwarf frog | Competes directly for food at the same level as the betta, and is frequently outcompeted and slowly starved. It also needs to surface, which is the betta’s territory. |
| A goldfish | Different temperature range, enormous adult size, enormous bioload. Wrong on every axis and still displayed together in shops. |
The pattern in every wrong answer
Almost all of them fail because a social species has been reduced to a number that fits the tank. The problem is rarely the betta - it is that a fish which needs six of its own kind has been sold as one. When you see a tank mate recommended as a single specimen, check whether the species shoals before you check whether the betta will tolerate it.
What we cannot tell you
Whether your betta will accept any of this. Individual temperament varies enormously, and a species that works in most tanks will still be killed in yours if your fish is one of the ones that will not tolerate anything. That is why the exit plan in the main tank mates guide is not optional.
What we would buy for this
Chosen from the same registry as our roundups, on published specifications and the arithmetic they imply - not on testing we have not done.
Fluval Spec Aquarium Kit, 16 US Gal
The point at which a nano tank stops being a compromise. Sixteen gallons is enough water to hold temperature through a power cut, enough length for a proper scape, and - this is the part that matters for this site - enough volume that a betta can actually have tank mates without you gambling on it.
Skip it if: The tank has to fit a desk. This is a 36-inch-wide piece of furniture's worth of tank once you allow for the stand and the maintenance clearance.
Java Fern
The other rhizome plant, and the one that gives a small tank height without needing a substrate. Same rules as anubias: tie it to wood, never bury the rhizome, low light, no CO2. It grows faster than anubias, which makes it the better choice if you want the plants doing real nitrate work.
Skip it if: You want a tidy plant. Java fern throws plantlets off its own leaves and will slowly colonize everything you tie it near.
Anubias Nana Petite
The single most useful plant in a betta tank. It attaches to hardscape rather than rooting, it wants low light and no CO2, and its leaves are stiff enough to hold a sleeping betta. Aquarium Co-Op publishes the numbers that matter: 10-20 PAR, no CO2 requirement, attach to rocks or wood.
Skip it if: You intend to bury the rhizome. Anubias rots when the rhizome is planted, and this is the most common way people kill it.
Frequently asked
What is the best tank mate for a betta?
At five gallons, a nerite snail - it is the lowest-risk addition available. At ten gallons and up, a small group of bottom-dwellers, which occupy part of the tank the betta does not defend.
How many tank mates can a betta have?
In a five-gallon, one or two invertebrates. In a ten-gallon, one small group of one species. The limit is bioload and territory rather than a count, and both scale with water volume.
Can a betta live with snails and shrimp at the same time?
In a five-gallon, that is already at the limit - a nerite and two Amano is a reasonable maximum. It works better in a ten, where the bioload and the territory both have room.
Why do shops recommend tank mates that do not work?
Mostly because the advice is generic to community tanks rather than specific to bettas and to nano volumes. A corydoras is a fine community fish; the failure is putting one of a species that needs six into five gallons.