The Danger of Overfeeding
Overfeeding is arguably the most common and dangerous mistake beginners make. A fish's stomach is roughly the size of its eye. When excessive food is dumped into the tank, whatever is not eaten within a few minutes will sink into the substrate and begin to decay. This decaying matter causes a massive spike in toxic ammonia, clouds the water, and fuels unsightly algae blooms. As a strict rule, only offer as much food as the fish can consume entirely within two minutes.
Choosing the Right Food Type
Fish inhabit different zones of the aquarium, and their food must match their feeding habits:
- Surface Feeders (e.g., Zebra Danios, Bettas): Prefer floating flakes or small floating pellets. Their mouths are generally upturned to take food from the surface.
- Mid-Water Feeders (e.g., Tetras): Do best with slow-sinking micro-pellets or granules that they can catch as they drift downward.
- Bottom Dwellers (e.g., Corydoras): Require heavy, fast-sinking pellets or wafers to ensure food reaches the substrate before other fish consume it.
Feeding Frequency
Adult fish generally only need to be fed once or twice a day. Many experienced aquarists even implement one "fasting day" per week to allow the fishes' digestive systems to clear and to encourage them to forage naturally in the tank. If you notice uneaten food resting on the substrate after feeding time, use a net or siphon to remove it immediately and reduce the portion size for the next meal.