How Much Should I Feed My Fish?

Overfeeding is one of the most common mistakes beginners, and long-time fish owners and breeders make. Giving your fish too much food can lead to a series of problems. 

For one, excess food and remnants can get clogged in the filter. Fish food can also break down into toxins that may be dangerous to your fish. Not only that, but your fish might also suffer from health problems like constipation, fatty livers, and bacterial or fungal infections. 

This article will provide you with information such as how much should I feed my fish, how often, what should I feed them, and other relevant information that you should know as a fish pet owner. 

Why do fish seem like they are always hungry? 

In the wild, fishes struggle to find a constant source of food. When they find a source, they make sure to eat them as quickly as possible. 

Even when they are already in aquariums, this trait has never faded. As such, these opportunistic feeders will eat whenever they get the chance, even when you had just fed them 15 minutes ago. 

Will they stop eating when they’re full? 

While opportunistic feeders, fishes do stop whenever they get full. This happens when their stomachs can no longer expand to take in more food. Usually, this means that indigestion has already occurred. 

Keeping up with this lifestyle, however, will have some severe repercussions on your fish, health-wise. 

What do fish eat? 

Different fish species eat different types of food. To feed them adequately, you will have to know what they eat in the wild. Fishes can be classified as such: 

Herbivorous Fish 

These fish types eat a fair amount of plant material in their diet. As such, they do well if you have numerous plant species in your tank. Because of that, herbivorous fish tend to forage over the day, requiring less fish food to eat. 

Carnivorous Fish 

Carnivorous fish partake in a lot of meat. In the wild, they have to hunt and catch their food first before they can eat. As such, they eat less frequently compared to other fish types. 

Omnivorous Fish 

Omnivorous fishes have it best as they can eat a variety of food. They also tend to be the greediest of all the types, which explains why they tend to eat whenever food is available, even when they aren’t hungry. 

Another factor to consider is the size of your fish. Large fishes usually don’t like eating small flake crumbles, whereas smaller fish species have difficulty eating large pellets. 

You also need to consider what type of feeder they are. Top feeders like to go to the aquarium’s surface and eat their food there. Floating pellets are their preferred food type. 

There are also mid-water feeders who eat their meals in the middle of your tank. Slow sinking food pellets are recommended. Lastly, there are bottom feeders who like to scavenge the tank’s bottom. You’ll need to buy rapidly sinking food variants for them. 

An example of specific diets would be: 

Goldfish diets: Goldfishes are omnivorous fishes and, thus, are good to eat anything. You’ll need to give them well-balanced and healthy meals packed with protein and fiber to help them get all the vitamins and nutrients they need. 

Betta fish diets: Bettas are usually one of the most common fishes beginners get. These carnivorous fishes do well with high-protein diets. They are also top feeders, and thus, they are suited to floating food pellets, frozen food, and live food. 



How much should I feed my fish? 

The amount of food your fish can eat varies on the type of fish they are. However, a good rule of thumb to follow is giving as much food your fishes can eat in 2 to 3 minutes. 

If you’re unsure, you can start by giving only a small amount and observe how quickly your fishes can consume it. If it’s gone in less than 2 minutes, then increase the amount. 

Remove any remaining food after 5 minutes using a net or a siphon hose. When in doubt, it’s always best to underfeed than to overfeed. 

How often should I feed my fish? 

Most fishes are okay with eating once or twice a day. Some fish tank owners even let their fishes fast one to two days a week to clear up their digestive systems. 

The size of your fish can affect their appetite. Larger and sedentary fish feed less frequently compared to tiny, energetic fish. Young, growing fish also need to eat three or even more times per day. The key is to give them smaller quantities more frequently to satiate their appetites. 

You’ll also have to feed slow grazers and herbivores more than once. Herbivorous fish like Farowellas, Mollies, Silver Dollars, and the like need to munch often since their small stomachs don’t hold much food. Feeding them often or providing them with live plants can help satiate their appetites. 

Goldfishes are also another example. Since they lack stomachs, it’s better to feed them sporadically and let them nibble on some plants. 

When should I feed my fish? 

Most fish species eat during early morning or dusk in the wild, with the exceptions of slow grazers, herbivorous and omnivorous fishes. While you can feed your fishes whenever it’s best to do this during these time frames. 

For the morning feeding, make sure to have your aquarium light on for 15 to 30 minutes before feeding your fish. This way, every inhabitant is awake and knows that it’s time to eat. 

For nocturnal species like catfish, knife fish, etc., give them at least 30 minutes after turning off your aquarium lights for feeding. 

Fishes quickly learn when they’ll get to feed. Over time, you’ll see them eagerly swimming at the surface or going out of their hiding places to alert you of feeding time. 

fish feeding

How long can a fish go without food? 

In the wild, most fishes are even lucky to eat once per day. More often than not, they are used to not eating compared to eating often. 

If you plan to go on a vacation out of town and the like, there is no need to worry. Adult fishes can survive one week without any food. Of course, this can also depend on their metabolism, size, and water temperature. 

Younger fishes and hatchlings, however, cannot survive as they need to be often fed. If you want to go on vacation, it’s best to set up an automatic fish food feeder or hire a fish sitter or ask someone to feed them for you. 

Is fasting good for your fish? 

You might have heard of some fish tank owners letting their fishes fast once or two days per week. Fasting depends on the fish type. 

Generally, large and carnivorous fishes are slow eaters and only eat occasionally. As such, you can opt to fast them if you wish. 

However, tiny and younger fish might not do so well with fasting since they have small stomachs and need frequent feeding. 

How do you know if you are overfeeding your fish? 

Overfeeding happens when you give your fish more food than it can eat. Here are some of the signs of overfeeding: 

  • Cloudy and foul aquarium water 
  • Excessive algae growth 
  • Filter media gets clogged quickly 
  • Fishes are sporting a swollen belly 
  • Fish show no interest in eating 
  • Foam or froth can be seen on the aquarium’s surface 
  • Growth of fuzzy white fungus in plants 
  • Increased levels of ammonia or nitrite 
  • Low pH levels Uneaten food 
  • Sudden explosive growth of worms and snails 

Overfeeding is dangerous since it can cause numerous health problems in your fish like bacteria or fungal infections, constipation, fatty liver disease, and the like. 

If you see these signs, make sure that you siphon out and get rid of uneaten food quickly. Then, you have to lightly vacuum the tank’s substrate and reduce the food amount by 50% until your fishes are eating normally again. 

How do you know if you are underfeeding your fish? 

You will know when you are underfeeding your fishes when their body colors seem to have grown duller, or they are slowly dying. If this happens, increase the food amount. 

However, note that these signs can also be symptoms of fishes suffering from internal worms and parasites. If you think you are feeding your fish usually but aren’t gaining weight, you might need to administer some deworming or antiparasitic medication. 


Overfeeding, while being a simple and common mistake, can lead to dire consequences. Not only does this affect the quality of life in your water tank, but it also inflicts severe repercussions on your fishes. 

Hopefully, this article has provided you with enough information, such as how much should I feed my fish, what to feed, how often and when, and other pertinent facts.

Feeding your fishes the right amount and at the right time and frequency will produce great results. You will soon find them having more robust immune systems, vibrant colors, increased energy levels, and having long healthy lives. 


Rita Wagener
Rita is a resident paw expert at Pet Keepers. A registered & licensed dog trainer, she also has a degree in animal nutrition, and runs her own dog training course.

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