THE PROBLEM: In my experience working in pet stores, this is one of the most common culprits of a dirty fish tank. Many aquarium keepers love to watch their fish eat, and often will offer food several times a day to see their little wet pets swim up to the surface to gobble up their meal. This problem is further exacerbated because many fish food companies list right on the packaging to feed your fish at least 2-3 times a day!
THE ISSUES: Fish naturally eat very infrequently, and in their wild environment, it is their instinct to eat food whenever it is available because they do not know when the next meal comes. Remember Dory from Disney’s Finding Nemo with the short-term memory? Most fish have memories have the same duration; they will eat, forget that they’re full, and then eat again just because food is there! A fish’s stomach is approximately the size of its eyeball, so they certainly do not require as much food as one may think, especially in a controlled captive setting! Consequently, in the close environment of your aquarium, not all the food offered makes it to the fishes’ bellies, and a lot of excess food ends up putrefying at the bottom of the aquarium.
THE SOLUTION: One moderate sprinkling of food daily is adequate for most fish, and many will do just fine eating every 2-3 days. Why, I once had a 30-gallon aquarium that housed approximately 24 fish of various sizes. For the majority of the time the tank was set-up, those fish got fed only once week. And I assure you, I had beautiful fish that were healthy and not skinny at all, some that I paid a lot of money for. Best of all, I had a wonderfully clean aquarium (plus, I didn’t have to buy fish food as often).