How Often Should You Feed Aquarium Fish, and How Much?

What the sources say

They agree on small meals and removing leftovers. They disagree on how many meals and how long a meal should last.

Source	How often	How much
A veterinarian, for PetMD	Once or twice a day, by species	What they eat in 2 to 5 minutes
A retailer’s guide	Most fish once a day, or two smaller meals	Until bellies look slightly rounded
A fish food maker	Two to three times a day	What they eat in 1 to 2 minutes
A veterinary manual	Varies with species, age, tank and temperature	Not stated as a time

A veterinary manual explains why no single rule fits: feeding rates vary with the species, its age, the tank and the water temperature.

Our advice for a beginner: start with one small meal a day for adult fish, or two smaller ones. Add a pinch, watch it go, and add a little more only if it vanishes at once.

Watch the bellies, not the clock

A retailer’s guide points out that some fish finish a meal in seconds and others graze slowly, which is why the minute rules differ. It suggests a better check: feed until the fish have a slightly rounded belly, not a stuffed one.

Then remove whatever is left. A veterinary manual lists feeding and removing uneaten food as a daily job. A food maker warns that uneaten food decomposes and can cloud the water, and our cloudy water guide covers what happens next.

Signs you are feeding too much or too little

Too much	Too little
Food left lying on the bottom	Thin bodies or sunken bellies
Swollen bellies and a lot of waste	Paler colors than usual
Algae, or a sudden boom in snails

A veterinarian writing for PetMD adds that poor feeding can lead to obesity, constipation, swim bladder problems and poor water quality. The same retailer’s guide warns that underfed fish look much like fish with internal parasites. If more food does not help, ask a vet.

Feed every fish where it eats

A veterinary manual says to know where your fish feed: at the surface, in the middle or at the bottom. It warns that bottom feeders should not get flakes that float.

• Bottom dwellers. Corydoras and plecos need a food that sinks. Check that it reaches the bottom before the fish above eat it all.
• Night feeders. A retailer’s guide says shy fish such as kuhli loaches may not come out in the day, and suggests a little extra food after the lights go off.
• Morning meals. The same guide suggests feeding day-active fish at least 10 to 15 minutes after the light comes on.

Each species page lists what that fish eats. Start from the fish list.

Young fish eat more often

A veterinary manual gives the reason: growing fish are fed about 3% to 5% of their body weight a day, against 1% to 2% for adults. A retailer’s guide suggests three to five tiny meals a day for growing fish. Keep each one small, because the water fouls just as fast.

Variety and treats

• One main food. A veterinary manual says commercial dried foods are usually made to hold the right mix of nutrients. It suggests one main food, with others added.
• Treats. A veterinarian writing for PetMD says frozen or freeze-dried treats should be offered only one or two times a week.
• Vegetables. A veterinary manual suggests vegetables a few times a week as a supplement for many fish. Remove what is not eaten.
• Live food. A veterinary manual warns that live food can bring in parasites or disease, and that fish fed only live food from the start may refuse anything else.