Overfeeding is the most common mistake in the hobby and the root cause of problems that look like something else entirely — cloudy water, algae blooms, ammonia spikes, bloated fish. Almost nobody underfeeds.
Feed less than feels right
A useful benchmark: what the fish finish in about a minute, once or twice a day. For a betta that is three or four pellets. It will look like nothing. It is the correct amount. Anything uneaten sinks, rots, and becomes ammonia, which is why a heavy feeder and a struggling filter usually turn out to be the same problem.
A fasting day once a week does most fish good, and clears up a surprising share of the digestive problems people bring to us.
Match the food to where the fish eats
Fish feed at different levels and a food that sinks past a surface feeder is wasted. Floating pellets and flakes for top and mid-water fish; sinking pellets and wafers for corydoras, loaches and plecos, which will not come up to compete and will quietly starve in a tank where everything is eaten before it lands. Carnivores, herbivores and the wood-rasping Panaque plecos all need genuinely different food, not the same flake in different packaging.
Variety, and frozen over freeze-dried
A quality staple pellet does the heavy lifting; variety does the rest. Frozen bloodworms, brine shrimp and daphnia are excellent a couple of times a week and noticeably improve color and conditioning. If you use freeze-dried, soak it first — it expands after it is swallowed otherwise, and that causes exactly the bloating people then treat as disease.
See also invertebrate food and supplements.
