Fish that may eat smaller tank mates
42 species are flagged predatory, likely to eat small fish, or both. Plan around adult gape, not shop length.
Mouth size at purchase is not mouth size at six months. These species are flagged predatory, or as likely to eat small fish, or both. Plan around adult gape, not the polite juvenile you saw in the shop. Anything that fits in the mouth is potential food. That includes shrimp, snails, fancy guppies bought small, and the fry of anything that breeds in the tank.
Predation does not run on a polite schedule. Most of these species hunt at dawn, at lights-out, or all night, which is when the rest of the tank is asleep. Stock the predator last, in a tank that already has cover and broken sightlines, and resist adding small fish later as decoration. Adult gape on a fully-grown specimen rarely matches what the shop tank suggests.
Every row is a real profile in the live library; filters are field-driven, not hand-curated blurbs.
Fish on this list
- African Cichlid
aggressive · intermediate · min 200L
- African freshwater butterflyfish
peaceful · intermediate · min 150L
- Agassiz’s dwarf cichlid
semi-aggressive · intermediate · min 80L
- Angelfish
semi-aggressive · intermediate · min 150L
- Assassin Snail
peaceful · beginner · min 30L
- Bala / silver shark
peaceful · intermediate · min 500L
- Banded leporinus
semi-aggressive · intermediate · min 300L
- Black ghost knifefish
semi-aggressive · advanced · min 500L
- Brown / hockey-stick pencilfish
peaceful · intermediate · min 100L
- Checkerboard cichlid
peaceful · intermediate · min 100L
- Chocolate gourami
peaceful · advanced · min 80L
- Cockatoo / crested Apistogramma
semi-aggressive · intermediate · min 100L
- Convict cichlid
semi-aggressive · beginner · min 200L
- Croaking gourami
peaceful · intermediate · min 80L
- Cuckoo / petricola catfish
peaceful · intermediate · min 200L
- Dojo / weather loach
peaceful · intermediate · min 150L
- Dwarf pencilfish
peaceful · intermediate · min 60L
- Electric Blue Acara
semi-aggressive · intermediate · min 150L
- Firemouth Cichlid
semi-aggressive · intermediate · min 200L
- Ghost Shrimp
semi-aggressive · beginner · min 40L
- Giant danio
peaceful · intermediate · min 200L
- Golden / Beckford's pencilfish
peaceful · intermediate · min 80L
- Golden dwarf cichlid (Nannacara)
peaceful · intermediate · min 50L
- Golden Wonder Killifish
semi-aggressive · intermediate · min 80L
- Green Terror
aggressive · intermediate · min 300L
- Jack Dempsey
aggressive · intermediate · min 200L
- Jaguar cichlid
aggressive · advanced · min 500L
- Keyhole cichlid
peaceful · intermediate · min 200L
- Moonlight gourami
peaceful · intermediate · min 180L
- Opaline gourami
semi-aggressive · intermediate · min 150L
- Oscar
aggressive · intermediate · min 300L
- Paradise fish
semi-aggressive · intermediate · min 120L
- Pea Puffer
semi-aggressive · intermediate · min 40L
- Pictus catfish
peaceful · intermediate · min 250L
- Rainbow cichlid
peaceful · intermediate · min 200L
- Red-tailed catfish
aggressive · advanced · min 2000L
- Ropefish / reed fish
peaceful · advanced · min 200L
- Senegal bichir
semi-aggressive · intermediate · min 300L
- Severum
semi-aggressive · intermediate · min 250L
- Silver dollar
peaceful · intermediate · min 300L
- Splash tetra
peaceful · advanced · min 80L
- Tinfoil barb
peaceful · intermediate · min 500L