FishBaseHQ

Freshwater compatibility chart

One species at a time, scored against the rest of this database. It is not a 200-fish poster from 1998. It uses the same rules as the checker: water type, temperament, overlapping temperature and pH, and whether the tank is big enough.

Yellow is a warning, not a maybe-it-will-be-fine. “May eat shrimp” means shrimplets become food. Temperature gaps do not close because you split the difference at 72°F. For a mix you already picked, the checker is faster than clicking every row.

Species

Betta

Community Fish

Livebearers

Cichlids

Catfish & Loaches

Bettas & Gouramis

Shrimp & Snails

Crabs

Goldfish & Pond

Pairwise check against the fish in this database at 20 gallons. A green cell is not a promise — it is “no automatic conflict.”

TankmateVerdictMin tankTemperament
Amano Shrimpincompatible10 galpeaceful
Angelfishincompatible29 galsemi-aggressive
Bristlenose Plecoincompatible25 galpeaceful
Cardinal Tetraincompatible15 galpeaceful
Cherry Barbincompatible15 galpeaceful
Cherry Shrimpincompatible5 galpeaceful
Clown Loachincompatible75 galsemi-aggressive
Common Goldfishincompatible40 galpeaceful
Common Plecoincompatible100 galpeaceful
Convict Cichlidcompatible20 galaggressive
Corydoras Catfishincompatible20 galpeaceful
Discusincompatible50 galpeaceful
Dwarf Gouramiincompatible10 galpeaceful
Electric Yellow Cichlidincompatible30 galaggressive
Ember Tetraincompatible10 galpeaceful
Endler's Livebearerincompatible5 galpeaceful
Fancy Goldfishincompatible20 galpeaceful
Fiddler Crabincompatible10 galsemi-aggressive
German Blue Ramincompatible15 galpeaceful
Guppyincompatible5 galpeaceful
Harlequin Rasboraincompatible15 galpeaceful
Honey Gouramiincompatible10 galpeaceful
Jack Dempseyincompatible55 galaggressive
Koiincompatible1000 galpeaceful
Kuhli Loachincompatible15 galpeaceful
Mollyincompatible20 galpeaceful
Mystery Snailincompatible10 galpeaceful
Neon Tetraincompatible10 galpeaceful
Nerite Snailincompatible5 galpeaceful
Oscarincompatible75 galaggressive
Otocinclusincompatible10 galpeaceful
Pearl Gouramiincompatible30 galpeaceful
Platyincompatible10 galpeaceful
Rainbow Sharkincompatible55 galaggressive
Red Claw Crabincompatible10 galsemi-aggressive
Swordtailincompatible20 galpeaceful
Tiger Barbincompatible20 galsemi-aggressive
White Cloud Mountain Minnowincompatible10 galpeaceful
Zebra Danioincompatible10 galpeaceful