How often should you feed aquarium fish?
AquaLog guide · Published
In short: Feed most adult aquarium fish once or twice a day, giving only what they finish in a couple of minutes. Fry need smaller meals more often. Healthy adult fish can usually go 1–3 days without food, so a short weekend away needs no feeder, but longer trips need a plan.
How often should adult fish eat?
Once or twice a day suits most community fish. The size of each meal matters more than the number: whatever the schedule, give only what the fish finish in a couple of minutes. Fish will beg at the glass whatever you do, so don't read that as hunger.
How much is one portion?
- Give a small pinch of flakes, or a few pellets per fish.
- Watch for two minutes. If it all goes in the first few seconds, add a little more.
- Anything still drifting or lying on the bottom after a couple of minutes was too much. Net or siphon it out, and give less next time.
- Make sure food reaches every level. Bronze corydoras and other bottom-dwellers need food that sinks; our care guide lists sinking pellets, frozen bloodworm and scraps from above for them.
How much fish eat changes with temperature, age and breeding, so keep watching rather than sticking to a fixed count of pellets.
Do all fish eat the same food?
No. Each species page in the care guide lists its diet. These are examples where the wrong food causes real problems:
| Fish | Diet type | Foods in the care guide | Problems the care guide lists |
|---|---|---|---|
| Bristlenose pleco | Herbivore | algae wafers, courgette, driftwood to rasp | Starvation without vegetable food. Bloat from protein excess. |
| Otocinclus | Herbivore | soft green algae, biofilm, blanched courgette | Starvation in algae-free tanks |
| Peacock cichlid | Carnivore-leaning | cichlid pellets, mysis, frozen foods; no excess protein | Malawi bloat from protein-rich diets |
| Pea puffer | Carnivore | live/frozen snails, bloodworm, blackworm; ignores dry food | Starvation on dry food |
| Chili rasbora | Micropredator | baby brine, cyclops, crushed micro pellets | Starvation from oversized food |
What are the signs of overfeeding?
- Food left on the substrate or in the plants after a few minutes.
- Cloudy or smelly water.
- Any ammonia or nitrite reading above zero in an established tank. Overfeeding is one of the main causes of high ammonia: the more fish eat, the more ammonia they produce, and uneaten food rots into more.
- Nitrate climbing faster than usual between water changes.
- A sudden boom of snails or algae, often fed by the surplus.
If you see these, cut portions back, siphon out leftovers, test the water and do a partial water change. While ammonia is above zero, feed very little or skip a day or two until it is back to zero; a short break does not usually harm adult fish, though fry are the exception. New tanks are especially easy to overfeed. See aquarium water parameters explained.
How should you feed fry?
Newly feeding fry have a high metabolic rate and a short gut, so food passes through quickly and they do better on small meals several times a day. In a study of fry of an Amazonian ornamental fish, Pyrrhulina brevis, those fed three or four times a day grew better than those fed once or twice, and the researchers recommended three feeds a day. Never fast fry the way you can adults.
Food size matters as much as frequency. Fry need food small enough to swallow, such as baby brine shrimp, finely crushed flake or food sold for fry. Even some adults have tiny mouths: the care guide lists starvation from oversized food as a problem for chili rasboras. More meals mean more waste, so a tank of fry needs small, frequent water changes.
Can fish go without food while you're away?
Healthy adult fish usually can for 1–3 days. University of Florida fisheries specialists note that stopping feeding for a short period, such as 1–3 days, does not usually harm fish, fry excepted. For a short weekend away, feed normally before you go and leave the tank alone. For anything longer, arrange feeding: nobody can promise that two weeks without food has no effect on a fish's welfare.
- An automatic feeder drops dry food at set times. Set it up a week or two before you leave, so you can check the portion size and make sure the food doesn't clump in damp air.
- A sitter with pre-portioned food. Put each day's food in a labelled pill organiser and put the rest of the food away. Well-meaning helpers often overfeed, and too much food is a bigger risk than a missed meal.
- Holiday food blocks release food slowly, but fish may ignore something unfamiliar, and the block still adds waste. Try one at home first.
- Before you go, do your usual water change a few days early, check the heater and filter, and don't add new fish.
Fry, sick fish and fish that need live or frozen food need a person to feed them. A pea puffer, which ignores dry food, can't be left with an automatic feeder.
How do you know you've got it right?
Active fish that clear each meal within a couple of minutes, and nitrate that rises slowly and steadily between water changes, mean your feeding is about right. AquaLog charts every nitrate test, so you can see whether a new food or bigger portions push it up faster. Start logging. For the rest of the routine, see the maintenance checklist.