It is very important that you do not overcrowd your tank. An overstocked tank leads to stress and disease. A general guideline is 1 inch of fish per gallon. However you should not place a fish that is meant to grow 10 inches in a 10 gallon tank. A common belief about fish is that fish growth is regulated by tank size. While it may appear that way to a beginner, these fish will never be able to achieve their natural lifespan and often show deformities of the spine or skull. These fish have higher stress levels and are more susceptible to disease. Please only choose species that will thrive in the tank you have chosen. One of the most abused species of aquarium fish is the goldfish. They have a very inefficient digestive system (they have no stomach so food passes quickly) and produce a lot of waste. They also can grow quite large and are a social species that should be kept in groups. This means they should not be kept in a bowl and ideally should be kept in at least a 40 gallon or larger tank or pond. As a result, goldfish are not an ideal fish for beginners.
