Difference Between Aggressive & Community Fish

One common mistake for green aquarium enthusiasts is placing aggressive species of fish in the same tank as community species. This leads to lots of stress and tension within the tank and usually quite a few fatalities. Knowing what fish mix and what fish need their space saves lots of headaches and money.

  1. The Community Tank

    • The majority of aquarium keepers start out with a community tank. A community aquarium is a fish tank where all the fish more or less get along and have similar requirements in terms of water hardness, temperature and filtration. Often these aquariums feature fish from one single corner of the globe, but this isn't required. Community fish must play well with others, or else they ruin the community. Tetras, livebearers and plecos are all good community fish.

    Aggressive Fish

    • Many hobbyists looking for a challenge will want to raise more aggressive fish. Some species of fish are highly territorial, predatory or simply bad-tempered. They need a lot of their own space, often requiring their own tank. Some may be OK with a few similarly-minded fish, like cichlids. If introduced to a community tank, an aggressive fish will wreck havoc on his neighbors and become very stressed itself. Piranhas and arowanas are classic examples of extremely aggressive fish.

    Finding Compatibility

    • There are many resources available to help you figure out what fish are compatible. The Internet and library are good places to start; you should be able to find out the temperament of every fish available at your local pet store. The sales clerks at a pet store are also helpful, especially if it is a more mom-and-pop operation. Don't impulse buy fish -- always research new potential buys. You don't want to introduce a fish that will kill everything else.

    Rules Are Meant to Be Broken

    • Aggressive versus community fish are very general terms that fail to capture the exact temperaments of the millions of species out there. Again, research is your best friend. Maybe a certain species, like the popular betta, is usually OK in a group of fish, but will viciously attack any member of its own species. Others will eat smaller fish but are totally fine around fish of similar size. Use the resources available and common sense.