Once you have learned to recognize and understand what your fish are doing, you may be able to interpret the forces driving the behavior that you observe. This will eventually lead to an improvement in your ability to provide better care for your pets, and to predict the effects of various changes or additions that you may introduce into the aquarium.

It is extremely important that you are able to recognize environmental problems that your fish's behavior might indicate. Many types of disease or harmful changes to your aquarium's environment will incite specific behaviors on the part of your fish. For example, constant swimming by a normally sessile species, such as the flounder (see color insert for photo), might indicate a water quality problem or that the animal is being harassed by a tank mate. Seahorses that are constantly in motion and swimming about are probably stressed for some reason. Similarly, bottom-dwelling fish rising to the surface might indicate a deficiency in oxygen, while color changes or listless behavior could presage disease or an environmental problem. Any unusual or atypical behavior on the part of your pets should send out a warning signal to you. The cessation of normal activities may also indicate a problem. Likewise, the refusal to feed may indicate that a female is gravid or that the animal is ill.