Fish may peck at tank mates for several reasons:
Dominance: Establishing hierarchy and territory.
Mating Behavior: Courtship rituals can involve gentle pecking.
Resource Competition: Overcrowding or food scarcity can trigger aggression.
Stress: Poor water quality or incompatible tank mates may cause hostile behavior.
Disease or Parasites: Irritation can lead fish to peck at affected areas.
Boredom: Lack of environmental enrichment may result in aggression.
Species Incompatibility: Mixing territorial and peaceful species often leads to conflict.
Providing adequate space, hiding spots, and good water quality can help reduce pecking and aggression.