Which species can actually live together?
Every pairing here is scored on the four things that actually decide whether two species cohabit: overlapping water parameters, compatible temperament, adequate tank size, and predator–prey risk. No vague “maybe.” A clear score, the real risk factors, and the conditions that make it work — or the alternatives that work better.
How the score works
Compatibility is not a yes/no — it is a set of conditions. Two species can be perfectly compatible in a 30-gallon planted tank and a disaster in a 5-gallon bare one. Our score weighs parameter overlap (do they want the same water?), temperament (will one harass or eat the other?), space (is there room to establish territory and escape?), and risk (what goes wrong, and how often?). A high score means easy success; a middle score means “workable with the right setup”; a low score means find an alternative.
Pair these pages with the interactive Fish Compatibility Checker to evaluate your own combinations, and the Stocking Calculator to confirm you have the space. New here? Start with the complete fish compatibility guide — the full framework behind every score.
Pairings
One of the best betta tankmates there is. Peaceful bottom-dwellers that occupy a different zone and ignore the betta entirely — just give them a group, sand, and enough tank.
Workable in a heavily planted tank with hardy adult Neocaridina, but never guaranteed — a betta is a predator and shrimp are prey. Plan for some losses and protect the babies.
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