when setting up a new aquarium, one of the primary concerns of the aquarist is that of balance. a balanced tank is essential to the success of a new aquarium. balance in oxygen content, waste removal, and plant life is important, of course, but the choice of the main types of fish can be used to achieve a balanced aquarium. the first type of fish is the community type.

community fish are, as their name implies, non-aggressive. many fish in this group are vegetarians and can be trusted not to eat other fish in the tank, but even those fish that are carnivorous will be compatible with their brothers if they are properly fed. mollies, swordtails, and angelfish are examples of community fish that can be safely kept in one tank. the second type that will meet the requirement of balance is the rough-fish type.

it is true that rough fish tend to be territorial. they mark off an area in the tank that is theirs, and they will not tolerate any intruders. these fish are aggressive to the point of killing any fish unable to defend itself. fire mouths, convicts, and silver dollars are members of the rough fish type that can be kept in one tank if they are provided with separate territories.

the third type, perhaps the most essential to a balanced tank, is the scavenger type. scavengers are a 'universal' fish and yet independent enough to be kept with rough fish. the scavenger's ability to live with all types of fish is important because it the housekeeper of the aquarium. it's eating eating habit is essential to to the balanced tank because it prevents excess food from fouling the water.

the, the algae-eater, and the banjo catfish are all excellent scavengers and compatible in any tank. a thorough knowledge of the three fish types and the fish that make up each type will save the novice aquarist many headaches later on. by carefully selecting compatible fish, the aquarist will achieve balance in his aquarium and assure himself of a successful tank.