Known Nippers
Tiger barb (not technically tetra but often grouped): notorious nipper.
Serpae tetra: aggressive fin nipper, especially in small groups.
Black skirt tetra: nips long-finned fish in small groups.
Buenos Aires tetra: largest tetra, nips and out-competes for food.
Peaceful Tetras
Neon, cardinal, rummy-nose, ember, lemon, glowlight, congo, diamond — all peaceful.
Hatchetfish, pencilfish (often grouped with tetras) are also peaceful.
- ✦Larger schools reduce nipping behavior.
- ✦Plant heavily to give nipped fish refuge.
Why Tetras Nip
In the wild, fin nipping is competitive — establishing dominance, claiming territory, or protecting food source.
Captive nipping is exaggerated by small groups (under 6), boredom, and proximity to long-finned tank mates.
Prevention Strategies
Keep nippers in groups of 10+ — internal social dynamics distract from outside fish.
Avoid pairing nippers with long-finned fish (bettas, angelfish, gouramis, fancy goldfish).
Plant heavily for visual barriers and refuge.
Feed adequately — hungry fish nip more.
Treating Damaged Fins
Improve water quality immediately. Add aquarium salt at 1 tsp per 5 gallons.
If wounds get infected, dose Furan-2 in a quarantine tank.
Fins regrow in 2-4 weeks if the source of nipping is removed.