Diet has much to do with algae growth. A common factor discouraging aquarists from keeping fish as pets is pollution of the fish tank. This is unnecessary and often is caused by something as simple as overfeeding your fish.

Most new fish owners consider that as long as the fish comes to the water surface eagerly, it is hungry, and so they add food as often as they like. The fear of a starving fish, away from natural sources of food is often at the root of new fish owners' anxiety.

Uneaten food falls to the bottom of the tank and stays hidden among gravel, rocks, or aquatic plants. In a short time, it starts to decay, disrupting the Nitrogen Cycle needed for a completely clean tank. Algae spores feed off the nutrients present in the food and begin to grow. Thus, it's this excess food that feeds algae, not your fish.

You can physically remove excess food pieces if you see any floating around a bit after the fish have eaten. If you find you have been overfeeding, you should clean the fish tank out completely and immediately by removing all water, cleaning the filters, and so forth. This will reduce the high levels of ammonia or nitrite, and will minimize chances of your fish getting diseased as well as reduce nutrients for algae to use.

Don't feel the need to feed your fish whenever you think it might be hungry. Follow a regular regimen of feeding, such as once in the morning and once at night. You should provide just enough food for the fish to eat what it needs in about three minutes, if you see that there is food left in the tank several minutes after you've fed your fish, you're either feeding your fish too much or too often. Either way, the food is going to waste and you're creating conditions for algae to grow and flourish in your tank.