Can Fish Eat Bread? Why or Why Not? (2024 Guide)

Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: July 6, 2024
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We’ve all been there – that sudden panic when we realize we’ve run out of pet food and can’t make it to the store in time. Frantically searching our home, we hope to find a suitable substitute to feed our hungry fish. While rummaging through the pantry, all we come across is bread. Is it safe for fish to eat bread? To discover the answers to this question and more about fish nutrition, keep reading to ensure your fish stay healthy!

Article Summary

  • Feeding bread to fish can cause digestive problems, constipation, and swim bladder disease, as well as harm the water quality, emphasizing the importance of a balanced and appropriate diet.
  • To keep your pets healthy, avoid feeding them human foods that are known to be harmful, such as chocolate, grapes, onions, garlic, avocado, and alcohol, and consult with your vet when in doubt.
  • To ensure fish receive a balanced diet, a variety of foods, including commercial fish food and live or frozen foods, should be provided in moderation while avoiding overfeeding.

Can Fish Eat Bread?

Person Feeding Fish with Bread

The realistic answer to this is that fish should not eat bread. While they technically can eat bread, feeding fish human foods such as bread can come with serious consequences to your fish’s health.

Not only will their digestive system have a hard time breaking down the bread itself, but their reproductive organs can be affected, along with causing liver problems, serious digestive issues and eventually death.

Even small pieces or dough balls can be an issue for fish and cause major health problems.

All the breadcrumbs floating around the tank will soak up water, causing them to swell inside of your fish. Fish simply shouldn’t eat bread as a part of their diet, even as a treat.

Do Fish Actually Eat Bread?

In the wild the obvious answer is that no, fish do not typically eat bread. In some instances such as ponds and park waterways, people may feed fish bread crumbs as something they consider to be a treat, but this is still harmful to their health.

Even the most resilient fish will have a hard time digesting the carbohydrates present in bread.

While many fish in freshwater ponds will greedily snap up anything thrown into their water, this doesn’t mean that this is actually the right food for them! People feeding bread to fish in public spaces can actually do more harm than good in the end.

Healthy Diet

While fish in the wild will eat anything that they can get to, this does not mean that we need to make a habit of feeding white bread to your fish. Remember to feed them what they need, not what we like!

What Happens if a Fish Eats Bread?

When a fish eats bread, the fish’s digestive system will act as per normal and attempt to break it down into its constituent nutrients.

The problem with feeding your fish bread is that as you can imagine, bread is super absorbent. In water, it can expand up to 1.5 times its original size, blocking off the large intestine and causing your fish to swell.


Think about this in terms of your fish’s poor stomach, all of that extra space taken up by the newly swollen bread can cause your fish to bloat. This is at the very least uncomfortable, causing constipation and death if the bread is unable to pass through their system.


Additionally, fish can’t digest yeast or gluten. Considering that most bread contains yeast, feeding bread to your fish is just asking for health consequences in the long and short term. A healthy fish needs a variety of foods based on their specific dietary needs and species.

Is Bread Good or Bad for Fish?

Feeding Beach Fish with Fish
Feeding Beach Fish with Fish

Bread is just plain bad for fish. Apart from the immediate choking hazard caused by bread swelling in water, there are other health problems that can arise such as constipation and bloating.

Eating bread is bad for fish health because it contains too many carbs and, depending on the bread variety, too much fat for their digestive system to handle properly.

Fish require a varied diet of protein and nutrients, which makes bread a bad choice when feeding your fish.

Just looking at the nutritional information on the package with all of the fat and carbohydrates should be a good indicator of why feeding fish bread is a bad idea.

Consult your local fish store of choice for information concerning which other foods make a good choice for your pet fish. Most fish eat a wide variety of food, and we should feed them what serves them best and keeps them healthy rather than what’s simply most convenient. 

Why Not to Feed Your Fish With Bread

If you decide to feed bread to your fish, you should know some of the potential hazards. Feeding bread to a fish not only comes with the physical dangers of choking, but can cause a variety of serious physiological effects down the road.

Health Risks When You Feed Your Fish Bread

  • Constipation – Since fish can’t digest bread easily, it can block their digestive system and cause constipation. Left unchecked, this can mean that aquarium fish die as they are unable to properly pass waste through their bodies. The backup of waste leads to a toxic shock to their system, killing them from within.
  • Swelling and Bloating – As the bread expands with additional water, so does the fish! The gluten inside of the stomach will be even harder to digest as it grows larger, meaning that even as the fish continues to feed after eating bread the blockage will grow.
  • This swelling damages the tissues of the animal’s organs, and can cause them to swim irregularly or bob to the surface as they become more buoyant.
  • Lower Metabolism – When you feed your fish bread, its system will begin to slow down as it expends more energy trying to break down the complex carbohydrates in the food. This lowering of the metabolic rate manifests as sluggishness, and means that your fish is suffering from serious health problems
  • Effects on Aquarium – The aquarium itself is affected by bread as well, as uneaten bits of bread can accumulate on the bottom of the aquarium and change the water quality.
  • Old bread rots, and eventually turns releases ammonia which over time can lead to ammonia poisoning and toxic shock affecting both plants and animals inside of your aquarium. Unlike solid foods, it can be very difficult to remove uneaten bread as it tends to dissolve and move around with the water flow rather than sit on the bottom.

Why Fish Can’t Eat Bread

Don't Feed the Fish Sign
Don’t Feed the Fish Sign

The stomach of a fish is designed to eat the foods it adapted to originally eat in the wild. This means for most fish live food such as plants and prey that are full of protein, vitamins and minerals.

Bread contains little to no amount of these things in a way that fish can intake easily.

When fish eat bread, their body has to work especially hard to attempt to break down the complex carbohydrates, gluten and sugars that they wouldn’t normally encounter in the wild. This can take a huge toll on their overall health.

Can I Feed Bread to Koi Fish?

Beautiful tropical fish such as koi and betta fish also do not need to eat bread!


They are adapted to eat foods full of protein (including other animals) and do not do well with attempting to break down complex carbohydrates.

If you try to feed bread to a healthy koi or betta you’ll see the same issues of constipation, bloating, and so on as you would with any other fish as they can’t handle the gluten.

What Other Human Food to Avoid

While there are some other human foods that fish can eat, it’s important to know what to feed your fish before just throwing anything you have in your kitchen into the tank. Some things to avoid when we feed fish include:

  • Fruits – The high acid and sugar content present in most fruit, along with hard to take in fiber means that fruit is a bad choice. Some soft fruits such as apples, bananas, and grapes can work, but should be cut into small, bite-sized pieces before your fish eat them.
  • High Carbohydrate Foods – Similar to yeast and gluten, complex carbohydrates found in wheat products and oats are incredibly hard for fish to intake. Even if not in the form of bread, these foods will likely be too tough for your fish to break down properly.

While smaller grains such as boiled rice or lentils may seem like a better option, they still contain little to no nutritional value for your fish and should be avoided.

  • Food With Yeast – Seeing as how fish lack the digestive enzymes needed to break down yeast and gluten, anything with yeast makes a bad choice for a healthy fish food. If you don’t know whether or not something contains yeast but think it might, it’s probably best left alone!
  • Meat With a High Fat Content – While some animal meats such as chicken and fish can make a good option in a pinch, high fat choices are a no go.
  • Fish lack the ability to break down large amounts of fat at one time since their natural diets consist of very little fat intake. This means that foods with high fats will be very difficult for them to turn into the energy that they need.

What Should Fish Eat?

Hand Feeding Koi
Hand Feeding Koi

There are still plenty of good options out there when we want to feed fish something nutritious.

Looking at your local pet store is a great place to start, as they’ll have not only a good selection but recommendations tailored to your particular species. Some good options around the house include:

  • Dry Fish Food – Fish flakes, pellets, and balls are all a good choice assuming they are designed for the species of fish you’re feeding. For example there are lots of great veggie options out there that might suit an omnivorous goldfish, but are not what a meat eater like the betta fish would prefer.
  • Frozen Fish – Bits of frozen meat and fish can be a great way to take something fresh and make it last longer. Frozen food has the added benefit of keeping away bacteria as it’s stored in a clean environment.
  • Vegetables – As long as your fish is either omnivorous or herbivorous, little pieces of veggies such as shelled peas, carrots, and cucumber can all make for a colorful addition to your fish’s diet. We recommend cooking tougher leafy greens such as spinach and lettuce, as the fibers need to be broken down to be easily digested by fish.


Whenever you want to try out something new for your fish, start small! Add one piece at a time and wait around a half an hour. If there’s still uneaten food, your fish probably doesn’t like that particular item and it should be removed before it can affect the overall water quality of the tank.


Throughout today’s article we’ve taken a look at the question of “Can fish eat bread?” While technically they can eat bread, the gluten and yeast are hard for them to digest which can lead to serious health issues.

This means that we should not feed bread to fish if at all possible, and should stick to natural food that suits their nutritional needs.

Feel Free To Share!

As always we hope that you’ve enjoyed today’s article and that it has answered all of your fish food related questions. Feel free to share with any other fish fanatics you may know, and we wish you good luck on your aquarium adventures!

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