How Long Can Fish Go Without Food (And Why)?

Exact Answer: 3 Days To A Week

It turns out that different kinds of fish can survive for different lengths of time without food. An example would be that some fish will only last a few days, while others can go several weeks without eating. 

A new study has found that most fish will starve within just two weeks of going without food. This finding could have big implications for the fishing industry and our understanding of the ecology of marine ecosystems. 

Contrary to popular belief, it is not constantly eaten when a fish is in an aquarium. Most fish will only eat around once a day.

6 15

How Long Can Fish Go Without Food?

Type of fishDuration
Betta1 to 2 weeks
Goldfish10 days

It depends on the type of fish and its environment. A fish that lives in a fast-flowing stream may only need to eat every few days, while a fish in a stagnant pool may need to eat every day.

Most fish can go without food for several days, but if they go for too long without eating, they will eventually die.

Fishes can go without food for a considerable period, depending on the species. Some fish can survive up to years without food, while others can last only for 3 days to 1 week.

The ability of a fish to go without food depends on the type of fish, the water temperature, and how active the fish is. Cold-blooded animals like fishes can go into a state of torpor (a deep sleep) that reduces their need for oxygen and lowers their metabolic rate. This allows them to survive long periods without food.

They have been living respiration for plants in lakes, rivers, and oceans even when food is scarce. However, in captivity, they may not be able to stand the deprivation for so much time due to overfeeding or lack of other forms of exercise that would help them conserve their energy stores. 

A fish will start going into a deep sleep before finally dying from either hunger or old age after all its fat reserves are depleted. This is because it will be unable to make enough usable energy through aerobic respiration with an insufficient level of oxygen in the water supply.

Why Would Fish Go Without Food For So Long?

When fish are food-deprived for long periods, their metabolic processes slow down; they eat less food because they don’t need it as much. The extra nutrients they take in go toward building up reserves rather than being used for energy or tissue production.

There are few rules of thumb for how long fish can go without food. Depending on the size of the fish, it could be weeks or months before they stop eating, but there isn’t an accurate way to determine this unless one knows more about the individual species of fish. 

Also, fish can go without food for 1 week because of their organs. This is because they have organs that provide them with nutrients they don’t need to take in through the mouth, like stomachs and intestines that extract calories from what they eat, thus helping them conserve energy. 

When a female mouth-brooding African Cichlid is carrying baby fry in her mouth, she may go up to a month without eating.

As a rule of thumb, bigger (adult) fish can go longer between feedings than smaller ones. Therefore, one should feed adult fish with sluggish metabolisms like goldfish once a day.

The most common reason for goldfish death is overfeeding. Even if one fed them previously, they will constantly eat, making it simple to overfeed them. Their metabolism slows down as they become older, but they are also cold-water fish. Hence, make sure to feed the fish as per their breeds.


Although the fish has a high tolerance for going without food for so many days, it is still not recommended to leave them starving before one goes away for a holiday. If one is planning for a longer vacation, buy an automatic fish feeder.

Larger and older fish are hardier since they have enough body mass and fat reserves to withstand long periods of hunger. Gourami fish, for example, will survive longer without food than a tiny Guppy.

There are various factors to consider depending on the size and type of the fish. Understanding the herbivores and carnivores is also important.


One request?

I’ve put so much effort writing this blog post to provide value to you. It’ll be very helpful for me, if you consider sharing it on social media or with your friends/family. SHARING IS ♥️