2026-10-28 · 11 min read
Best tank mates for specific species
Tank mates for bettas, neon tetras, cherry shrimp, and corydoras — plus the fish that should live alone. Use the compatibility checker before you buy the mix.
There is no universal community list. There are species with habits. Profiles: fish database. Pairwise check: compatibility. Chart view: compatibility chart.
Green on the checker means “no automatic conflict.” It does not mean skip quarantine, and it does not mean your male betta has read the chart.
Betta
Possible: snails, sometimes cherry shrimp in a heavily planted 10 if he is not a hunter, quiet bottom fish if the tank is actually big enough and he is not a maniac.
Usually not: other male bettas, guppies with long fins, danios, tiger barbs, anything that nips.
A female sorority is a project, not a community. Use the betta checker. Profile: betta.
Neon tetra
Yes: a bigger neon school, harlequins, corydoras, otos, small rasboras, a bristlenose in a tank that is not a 10.
No: large cichlids, anything that sees a 1.5-inch fish as a snack. Angelfish eat neons when they grow up. The cute juvenile in the cup is still a cichlid.
Neon tetra. A working 20-long mix: how many in a 20.
Cherry shrimp
Yes: other shrimp, nerites, a peaceful nano school that cannot fit a shrimp in its mouth.
Best: a species tank. Babies are food. Amano adults last longer than cherries next to fish.
No: angels, hunting bettas, gouramis with nothing else to do, almost anything “semi-aggressive.”
Shrimp and fish compatibility. Shrimp guide.
Corydoras
Yes: most peaceful midwater schools. They want six of their own, sand, and food that reaches the bottom.
No: large cichlids that claim the sand, goldfish that out-eat them, gravel that shreds barbels.
Corydoras. They are not an algae crew. They sift leftover food. Feed them.
Guppies
Yes: other peaceful livebearers, corys, a shrimp tank if you accept some fry loss.
No: fin-nippers. Male guppies with big tails are a betta’s hobby. Mix sexes and you will need a plan for fry.
Oscars, Jack Dempseys, mbuna, rainbow sharks
These are not looking for tank mates from the tetra aisle. One shark per tank. Oscars want a bathtub, not a 29. Aggressive fish.
How to use this
Pick the species you already want. Add the others in the checker at your real gallons. If the verdict is red, believe it. If it is yellow, read the flag — “may eat shrimp” means may eat shrimp.
Then run stocking. Compatibility is not a waste budget. A peaceful mix can still over-ammonia a 10.
Also on the blog
- Why is my aquarium water cloudy?
Cloudy aquarium water is usually a bacterial bloom, overfeeding, or stirred substrate — not a mystery. Test ammonia. Do not dump clear-water potions first.
- How often to change aquarium water
Most stocked community tanks want a weekly 25% water change. Goldfish want more. Test nitrate and dose conditioner for the new water, not the whole tank.
- How many fish can fit in a 20-gallon tank?
A 20 gallon long can hold a tetra school and corydoras. A 20 high is worse for swimming. Inch-per-gallon is not the answer — adult size, waste, and filter GPH are.