What Does It Mean When Two Fish Fight?

Watching your fish swim around the aquarium is generally a relaxing and peaceful experience, but if one of your fishes suddenly becomes the reef bully, you may find yourself refereeing a fin-nipping fighting match. Understanding what is at the root of fish aggression can help you choose an appropriate remedy.

  1. Territory

    • Redecorating your fish habitat may restore the peace.

      Like other animals, fish are capable of engaging in violent disputes over food and territory. Most often, a fish is more territoriality aggressive against fish that are of the same sex and breed or a similar size and color. If you have a fish that has staked a claim to an aquarium element or area, you may have to redecorate his habitat to reestablish the peace. Provide a variety of barriers to block the bully's view, and make sure his chosen territory is visually stimulating. Since a fish will only react to what he is able to see at any given moment, you can reduce the likelihood of disputes by reducing opportunities for fish-to-fish interaction.

    Hierarchy

    • When one fish decides to establish dominance over another fish in your tank, he is most likely attempting to secure his place in the overall pecking order of his community. You can use a net breeder to section off a portion of the tank, creating in effect a "fishy jail," until the less dominant fish become more confident in the bully's presence and the established order rearranges itself. If the bullying is severe and is not alleviated by temporary partitioning, you may have to remove the dominant fish to a separate tank to ensure the safety of your other fish.

    Schooling Behavior

    • Sometimes, adding to the size of a school can restore peaceful play.

      Some types of fish, such as tiger barbs, enjoy schooling and will chase each other playfully around the tank. If their school-size is too small, however, they may resort to nipping at each other's tail fins or bumping heads. The solution to this type of aquarium brawl is simply to add more same-breed fish to the mix. A school-size of at least six fish should keep the swim peaceful and fun.

    Weak Ones

    • Separate an injured and bullied fish to give it time to heal and regain her confidence.

      Sometimes, a fish or group of fish may repeatedly single out a weaker fish for abuse. If you notice a particular fish is constantly being attacked, injured or picked on by one or more of her aquarium mates, consider isolating the bullied fish for a time in her own small tank. She may need time to rest and heal from her injuries, and the break may also give the bullying fish a chance to turn their attentions elsewhere. You can reintroduce the weaker fish back into her community when she has regained her physical health and fishy confidence.