What to Feed Fish When you Run Out of Fish Food?

Fish rank as the third favorite pet for many Americans. Cats take the lead, followed by dogs.

But it’s no wonder fish are becoming a favorite. 

Compared to other pets, fish carry all the perks:

  • Don’t make noise – You’re assured of a peaceful sleep throughout the night.
  • Don’t leave fur everywhere – There won’t be fur on your hair when you snuggle on the couch.
  • Calm your mind – Watching fish swim in your aquarium reduces anxiety and improves blood flow.
  • Need little maintenance – Fish only need to be fed and kept in clean water.
  • Improve your home decor – Fish are aesthetically pleasing and add vibrance to your home.

If anything, fishes are quite the catch for pet lovers like yourself.

But while they’re often non-troublesome, there are days when you’ll hit a bump.

One day, the fish food runs out and the fish will skip a meal or two.

If it’ll be a while before you can rush to the pet store, then you might start worrying about starving them.

The good news, though, is that doesn’t have to happen.

When the fish food runs out, your home has got practically everything you need to feed your fish.

Let’s find out what foods at home serve as excellent alternatives to fish food.

Alternative Fish Food for Herbivore and Omnivore Aquarium Fish

Similar to human beings, fish have nutritional requirements necessary for healthy growth and survival:

  • Vitamins
  • Carbohydrates
  • Proteins
  • Mineral salts 
Alternative Fish Food for Herbivore and Omnivore Aquarium Fish

These dietary needs are met depending on if the aquarium fish are either freshwater fish or saltwater fish. 

The two groups are further subdivided into three categories based on what the fish eat:

  • Herbivores – Survive mainly on a plant-based diet.
  • Carnivores – Survive mainly on a meat-based diet.
  • Omnivores – Survive on a balanced plant-based and meat-based diet.

For omnivores and herbivores in the wild, their nutritional needs are fulfilled by feeding on algae and plant matter in the water. Omnivore fish also feed on small fish to obtain high protein meals.

So, if your aquarium fish are omnivores or herbivores, let’s review some natural alternative foods to consider.


There are many different kinds of vegetables suitable for feeding your fish. They include:

  • Green leafy vegetables like lettuce, spinach, Brussel sprouts, and broccoli
  • Zucchini
  • Cucumbers
  • Sweet potatoes
  • Peas
  • Lima beans

To prepare leafy vegetables:

  1. Wash them thoroughly with running water.
  2. Boil them for 8 to 12 minutes. For soft vegetables such as spinach and lettuce, boil for 3 to 5 minutes to avoid overcooking them.
  3. Strain the water.
  4. Allow the boiled vegetables to cool.
  5. Cut the boiled vegetables into bite-sized bits.

To prepare zucchini and cucumbers:

  1. Wash them thoroughly with running water.
  2. Cut them into small pieces.
  3. Remove the seeds.
  4. Boil three cups of water in a pot.
  5. Add the chopped pieces into the boiling water for two minutes.
  6. Remove the blanched pieces from the boiling water using a slotted spoon.
  7. Allow the blanched pieces to cool.

To prepare sweet potatoes, peas, and lima beans:

  1. Peel the sweet potatoes and shell the peas and the beans.
  2. Wash them thoroughly in running water.
  3. Boil them in medium heat until soft.
  4. Allow them to cool.
  5. Cut them up into small pieces.


For a kick of carbohydrates, fish love to eat boiled rice.

To prepare boiled rice for your fish:

  1. Wash and rinse the rice thoroughly in running water.
  2. Bring a pot of water to boil. The amount of water you use is dependent on the amount of rice. For instance, pour two cups of water for one cup of rice.
  3. Add the rice to the boiling water. Let it cook for 20 minutes.
  4. Once cooked, allow it to cool.
  5. Add one or two teaspoons of boiled rice into the tank.


Fish like fruits just as much as you do. The following are suitable to feed your fish:

  • Bananas
  • Watermelons
  • Apples
  • Strawberries
  • Pears

However, feeding fruits to your fish frequently increases the acidity level of the fish tank.

High acidity levels accelerate the growth of algae to unwanted quantities in the tank.

Therefore, to maintain the pH levels of the fish tank, feed them sparingly. Once or twice a week will do.

Note: Avoid canned fruits and vegetables. Canned foods aren’t suitable for fish as they contain harmful preservatives. 

Instead, opt for fresh and frozen fruits and vegetables. They’ll keep your fish well-fed and healthy in the long run.

Alternative Fish Food for Carnivore Aquarium Fish

Herbivore and omnivore fish are easier to care for since there are many options of human food to feed them. 

But with carnivore fish, human food choices are limited. 

Carnivore fish survive on a high protein diet that’s achieved by eating fish and other small sea creatures in the wild waters. 

However, it’s easy to replicate this natural meat diet when fish food runs out.

Below are food alternatives in your home that carnivore fish will eat:

  • Hard-boiled egg yolk
  • Brine shrimp
  • Blood worms
  • Live worms such as earthworms
  • White fish such as cod and tilapia
  • Beef heart

Note: Omnivore fish eat meat-based foods too, at a moderate level. 

If you use hard-boiled egg yolk, keep in mind that it can turn milky and cloudy in water.

So, if you rely heavily on this food source you might need to change your water more frequently. When to Remove Uneaten Food From the Fish Tank

The recommended amount of food to feed your fish is an amount they can finish in two to four minutes. 

But sometimes, there are leftovers in the tank.

To avoid overfeeding your fish and making the tank dirty, it’s important to remove all uneaten food within 15 to 30 minutes after feeding them.

Some people prefer to clean up the leftovers after 24 hours. But there are risks associated with letting fish food stay in the tank for long periods.

Decomposing fish food has the following effects:

  • Reduces dissolved oxygen in the water as decomposition uses oxygen.
  • Releases ammonia and nitrates that are toxic for your fish.
  • Increases carbon dioxide in the tank, thus increasing pH levels.
  • Causes your fish digestive problems when they eat the food.
  • Accelerates mold growth in the tank

Note: If the tank is turning cloudy fast, yet you remove leftovers within the recommended time, it means the fish is overfeeding, hence defecating often.

Alternative Foods You Shouldn’t Feed Your Fish

It’s cheap and exciting to feed human food to your fish.

But while humans have stronger and more evolved digestive systems, some of our food choices aren’t a good match for fish. 

Keep away from feeding your fish the following foods if you want them to be healthy and live long:

  • Beef and chicken – Beef and chicken contain fats that are hard for the fish to digest. 
  • Bread and pancakes – Although humans love to eat bread, the wheat in it causes fish to bloat. Bloating increases the likelihood of the fish to constipate. Constipation can be fatal for fish.
  • Sugar – Sugar, except in fruits, isn’t recommended for fish. Sugar causes your fish to dehydrate by absorbing the water in their cells since sugar is osmotic. 

Eventually, large amounts of sugar in the tank turn the water into a sugar syrup.

The syrup absorbs all oxygen and your fish will die from both dehydration and suffocation.

How Long Can Fish Survive Without Food?

A grown, healthy fish can survive from four to seven days without a feeding.

Some fish species can go as long as two weeks without food.

Therefore, you shouldn’t worry nor panic when you run out of fish food. 

How long a fish survives without food is dependent on:

  • Size
  • Age
  • Diet
  • Type

Large and older fish will survive longer than small young fish.

On the other hand, carnivore fish will last longer than herbivore fish since herbivores need to be constantly fed while carnivore fish don’t.

Finally, freshwater fish will succumb to hunger faster than saltwater fish because saltwater fish are used to food scarcity while freshwater fish aren’t.

Want to Learn More on How to Take Care of Your Fish?

As a fish pet owner, it’s important to educate yourself constantly on how to best care for your fish.

Check out the following articles to learn more about your fish: