The most common problem which confronted novice Aquarists was overfeeding their fish. This guideline can be exceeded, but the aquarium will require more frequent water changes and a power failure or disease under crowded conditions can cause a major wipe out. Dosages range from one-half to two teaspoons per gallon. Aquarium salts are available at pet stores, however, non-iodized table salts are much cheaper and work just as well. The only drawback occurs when aquarium water spills on the outside glass and evaporates leaving a film which can be difficult to remove.
Many aquatic habitats contain rock which provides structure and cover for fish.
This natural and also attractive feature can be realistically duplicated on a small scale in aquariums. Shale and limestone are the easiest to work with and the latter also doubles as a buffer which prevents the pH of water from going acid. The Darter Editor favors contouring gravel with rocks to form terraces which are honeycombed with crevices and caves for fish. Live or plastic plants add a nice final touch on the upper level. Rocks can be purchased from pet stores or collected from streams, lakes, or quarries.