How Often Do You Feed Fish (and How Much)?

If you’re new to aquariums, figuring out how to feed your pet fish can be a little confusing. They always come up to the glass and beg for food, but does that mean you should give it to them? Keep reading to learn all about how much and how often to feed fish, what to give them, and how long they can go without food if you’re on vacation.

What Do Fish Eat?

When looking at rows and rows of fish foods at the pet store, it becomes clear that not all fish eat the same thing. The ingredients in betta fish food versus goldfish food can be quite different. So how do you know what to feed your fish if their picture isn’t on the jar label? It’s time to do some research on your fish and find out:

• Are they carnivores, herbivores, or omnivores?
• Do they prefer to eat dry prepared foods, frozen foods, or live foods?
• What size food best fits in their mouths?
• Do they need floating or sinking foods? (Some fish eat from the top, middle, or bottom of the aquarium.)
• Is the food tasty to your fish, and does it get eaten quickly?

Other considerations also include the price of the food and quality of ingredients. If you’re curious about our 5 favorite high-quality fish foods, read the full article here.

Most people think of fish foods as flakes, pellets, and wafers, but you can also feed frozen, freeze-dried, gel, or live foods to provide more nutritional variety for your fish.

Some frequently asked questions we get about the diets of specific aquarium fish include:

• What do goldfish eat? These hungry omnivores eat almost anything – meat, vegetables, algae, and even debris found in the aquarium. Provide them well-balanced and varied meals with both protein and fiber to ensure they get all the nutrients and vitamins they need. See this collection of goldfish foods for our recommendations.
• What do betta fish eat? Bettas prefer a more carnivorous diet that’s high in protein. They also have upturned mouths that are well-suited for eating floating foods like betta pellets or freeze-dried foods from the surface of the water. However, they will also readily eat frozen and live foods. See our collection of betta foods for examples of what we feed our bettas.

How Often Do You Feed Fish?

Most fish are fine with being fed once a day, but you can also choose to feed them two smaller meals a day for more enjoyment. Growing babies and slow grazers often need access to constant food, so you may need to feed them three to five tiny meals each day or a long-lasting food like Repashy gel food that doesn’t break down as quickly in water.

When is the best time to feed fish? Most fish are awake during the daytime, so pick a fish feeding time that is at least 10 to 15 minutes after the aquarium light turns on. That way everyone is awake, alert, and ready to eat. However, if you have nocturnal species like kuhli loaches or plecos, make sure to feed them after the aquarium lights have turned off for the day. Since the other fish are less active in the dark, this extra nighttime feeding gives them a better chance of getting enough food.

Nocturnal creatures like kuhli loaches may be too shy to come out and eat in the daytime, so make sure to provide some extra food when the lights are off.

Is fasting good for fish? As mentioned before, it depends on the fish. Some people choose to skip one or two days of feeding to ensure that overfeeding doesn’t become an issue and cause health issues. In fact, large predatory fish may only need to eat a few times a week. Nano fish and baby fry, on the other hand, have smaller stomachs and generally need to eat more frequently.

How Much Should You Feed Fish?

You often hear general guidelines like, “Feed as much as your fish can eat in 5 minutes,” while others insist that 30 seconds is all the time their fish need to wolf down their meals. The reason that opinions vary so greatly is because some animals are fast eaters and others are very slow. Even individuals of the same species can have different feeding behaviors. My betta fish would hunt down every scrap of food and gorge himself to the point of bursting, whereas my nephew’s betta fish was extremely picky and would only eat if the food was placed exactly 4 mm in front of his mouth.

A better way to judge the appropriate portion size for your fish is by observing the roundness of their bellies from both the top and side views. If you have ever been to the vet’s office, you may have seen a chart showing the obesity levels in dogs and cats based on the widths of their bodies. In the same way, you should aim to feed your fish until they have a slightly rotund abdomen. Of course, this may be difficult to determine with naturally round animals, like certain goldfish and balloon mollies, so look online to find pictures of healthy fish as a reference point.

How Do You Know If You Are Overfeeding Fish?

If your fish has a swollen belly, is producing a lot of poop, or is not very interested in eating during mealtimes, they may be consuming too much food. Other signs can include piles of uneaten food at the bottom of the tank (which may grow fuzzy fungus over time), algae growth, or a population explosion in snails and worms. Because excess food quickly pollutes the water, you may also notice cloudy water problems, foam at the water surface, or high levels of ammonia, nitrite, or nitrate measured by a water test kit.

Betta fish are prone to overeating, so feed them just enough food to have a slightly rounded abdomen without any excessive bulging.

Overfeeding can ultimately cause health issues such as fatty liver disease, constipation, or bacterial and fungal infections from the poor water quality. Luckily, the solution is fairly straightforward – feed less food, remove any uneaten food after 10 minutes, and consider introducing a weekly fasting day to give your fish’s body a little break. Also, make sure that other family members or roommates are not feeding your fish throughout the day without your knowledge.

How Do You Know If You Are Underfeeding Fish?

If your fish have skinny bodies or sunken bellies, are displaying paler colors than normal, or are slowly dying off one by one, you might need to increase their portion sizes. Just be aware that these signs are also very similar to the symptoms of a fish with internal parasites or worms. So if you are feeding your fish plenty of food but they cannot seem to gain weight, they may need some antiparasitic or deworming medication to rid them of any unwanted hitchhikers.

How Long Can Fish Go Without Food?

If you are planning on traveling out of town or going on vacation, you may not need to worry. Adult fish can often go one week without any food, depending on their size, metabolism, and the water temperature. However, if you have a tankful of newborn fry that require constant feedings, it may be best to set up an automatic fish food feeder or find a pet sitter who can take care of their needs.

Why Are My Fish Always Hungry?

In the wild, fish are not always lucky enough to find food every day, so if they come upon a source of nutrients, they gobble down as much as possible in case they can’t find anything to consume the next day. Therefore, these opportunistic eaters constantly act as though they are starving, even if you just fed them 15 minutes ago.

Don’t let your fish’s excitement fool you into feeding them more than they need. Instead, you can divide their daily meal into two or three portions so that you can enjoy feeding them multiple times a day.

Will fish stop eating when they are full? Generally speaking, yes. When their stomachs can no longer expand, it is physically not possible to fit in more food until some digestion has occurred. However, if they eat until they’re completely stuffed every single day, obesity and other health issues can become a problem.

If you’re interested in feeding a wide variety of high-quality foods, check out our top 5 favorites list to learn more: