What Is the Most Aggressive Tropical Fish I Can Keep in a Tank?

When planning a new aquarium, it's important to know what fish can live well together. Some fish, such as cichlids and bichirs, are aggressive and require special attention.

  1. Bettas and Gouramis

    • Bettas can be extremely territorial. Although females are sociable, males should never be kept together. However, they can be kept with other peaceful fish. Gouramis, a species similar to bettas, are not as aggressive but can be territorial if their tank is not spacious enough.

    Cichlids

    • Although aggression in cichlids species varies, some, like the Malawi cichlids, are territorial and will nip other fish's fins. To solve territory problems they should be kept in large tanks where they won't feel the need to assert dominance.

    Bichirs and Knifefish

    • Bichirs, which are snake-like fish, and knifefish, are carnivorous. Because of this they will eat any fish smaller than themselves. They should be kept only with fish larger than they are, such as large catfish.

    Sharks

    • Not all aquarium shark species are aggressive, but some, like the red-tailed black shark, can be very territorial. Others, like the Paroon shark, may not cause harm to other fish but will ram into tank walls and obstacles.