What to Feed a Fish When out of Fish Food

It will happen to you. Get the box of fish flakes and give it a shake. Empty.

Go to the fridge for some blood worms or brine shrimp. All gone. Your first reaction is to panic…what if my fish EAT each other!

Not to worry, you probably have plenty of options in your home, right now.

The truth is, so many people buy their fish food commercially prepared or packaged that they forget there once was a time when tropical fish keepers foraged, grew, or prepared food for their fish collections. 

You can too.

What you learn here just might convince you that it is easier and more cost-effective to use self-prepared foods to help keep your fish healthy, happy, and out of a tank mate’s meal plan.

How Long Fish can Live Between Feedings

If you have to miss a day of feeding your fish, don’t worry, they will be fine. Most fish can survive a day or even two days with no introduced food before eating tank mates or tearing up the vegetation in your plants. 

Ultimately you don’t want to force your fish into a position of eating each other, and you probably already have something in your household that will serve as alternative fish food until you can get to your aquatic supply store, order online, or just get creative and start making your own fish food.

Making Fish Food at Home

Yes, it’s a thing. 

Many keepers have discovered the joy of cooking or preparing fish food at home from natural ingredients such as vegetables, seafood, captured insects, and invertebrates. 

Pro Tips: Home-made fish food can cost less than purchased, prepared foods. 

No matter where you live in the world, there are options available for alternate fish food. Try this… take stock of what you have in your pantry, your refrigerator, and your icebox right now. 

You probably have at least some vegetables such as squashes, lettuces, or potatoes. You may have whole or ground meats or seafood such as calamari, clams, or shrimp. Any or all of these may be fresh or frozen, and all can be great fish foods. 

Now take a look around your house or living quarters.

If you have a yard, you probably have earthworms and various forms of grubs. Fruit left on countertops will attract fruit flies. You have options. Let’s explore some choices for different types of fish.

Alternate Herbivore Foods

Herbivore species of fish are the easiest to keep fed because they accept various fruit and vegetable foods. Great options include:

  • Apples such as Granny smith
  • Broccoli
  • Brussel sprouts
  • Cauliflower
  • Cucumber
  • Green or unripe bananas
  • Peeled grapes
  • green beans
  • Lettuces
  • Peas
  • Potatoes
  • Rice, boiled and soft
  • Spinach
  • Squash such as zucchini
  • Yellow beans

Leafy vegetable tops, lettuces, and soft foods such as unripe bananas can be added directly to the aquarium. Other foods such as zucchini should be blanched or parboiled [briefly boiling] to make them softer before adding them to the aquarium. 

These vegetables can be frozen into feeding-sized portions and added frozen to the tank. Upper strata fish will peck at it as it thaws and then sinks, offering feeding opportunities for mid and lower strata species.

Alternative Omnivore Foods

Good news for you, omnivore fish species are almost as easy to feed as herbivores. 

They will eat the same foods plus some protein foods. The proteins can be any mix of insect, invertebrate or lean meats. If you have a composting bin in your yard, it can yield a source of insect proteins for your fish.

The gamut of protein choices will vary depending on where you live and what your diet is. The broad range includes:

  • Beef, very lean or organ meat such as heart
  • Bloodworms
  • Calamari
  • Chicken
  • Crabmeat
  • Crickets
  • Earthworms such as red wrigglers or nightcrawlers
  • Fruit flies
  • Fish, especially lean such as cod
  • Grubs
  • Maggots
  • Mealworms
  • Shrimp

Pro Tips: These foods do not need to be cooked but should be chopped to sizes that your fish can eat. 

Some keepers will combine vegetables and meats into a type of mash in a binding medium such as agar or gelatin. Look at the recipe for snail jello in the invertebrate section of this article as a guide.

If you use agar powder as a binder, you will need heat. Follow the instructions on the agar powder container. To feed your fish, just drop a block in the tank.

Care should be taken when feeding proteins. Uneaten food will spoil quickly and can contaminate the water. You should monitor your aquarium daily and remove uneaten food that your bottom feeders have not taken care of.

Alternative Carnivore Foods

The main difference between carnivore and omnivore diets is the emphasis on protein and the method of delivery

Often carnivore species are hunters. That is not to say they will not eat foods presented for omnivores, but their preference is for live or dead whole prey. 

To feed alternate foods to carnivores, consider the size of the food you normally give them.

For example, if you are using feeder goldfish, a similarly sized shrimp right out of the bag may be of interest. Similarly, a piece of cod might get their attention and make a meal.

Any of the foods from the Omnivore list will work for carnivores. Don’t be surprised if they also will peck at vegetables introduced for other species in the aquarium. Carnivores are opportunity feeders.

Species such as puffers need hard-shelled foods to keep their always-growing teeth in check. The clams you get at the fish store are similar to steamer and manilla clams you can get at the grocery, both fresh and frozen. Puffers will eat shrimp as well though this does not help with their need to crunch.

Alternative Invertebrate Foods

Species such as shrimp and snails have special dietary needs.

While they eat algae and plankton, they also need calcium. In the wild, this would come from natural sources, but you need to provide it in the aquarium.

Some keepers have developed a food mix generically named snail jello. This is a mix of vegetables and ground calcium antacid tablets held together with gelatin or agar.

Here is a very basic recipe, the contents can be varied to provide foods for omnivore species as well.

  • Grind 2 to 3 calcium antacid tablets into powder. Do not use mint tablets…stay with fruit-flavored varieties.
  • Cut vegetables such as squash, spinach, and peas into pieces small enough to blend.
  • Process the vegetables and calcium powder in a blender.
  • Take unflavored, unsweetened gelatin and mix according to directions.
  • Add the vegetable calcium mix to the gelatin.
  • Pour into ice trays or other small molds and refrigerate until set.
  • Bag the snail jello cubes and freeze.
  • To use, drop the cube into the tank. Your snails and shrimp will find the blocks and consume happily.

What not to use for Fish Food

A good rule of thumb for feeding is to keep base foods or ingredients as natural as possible. Here are a few guidelines on what not to use:

  • Avoid fatty meats and fish
  • Stay away from very sweet fruits such as red apples and oranges
  • Do not use heavily processed human foods such as bread
  • Don’t experiment with candies or similar treats

Your experiences with emergency fish feeding may lead you down the path of creating food for your species.

Fish keepers worldwide have discovered how rewarding and cost-effective it can be to feed fish with the same healthy ingredients you use for your cooking. 

Keep a supply of emergency fish food on hand, and you might discover the joy of cooking for your fish.

If you are looking whether you can put a saltwater fish in an aquarium of freshwater, we have the answer for you.

Or If you have a 10-Gallon aquarium tank and wonder how many fishes can you fit in it, we also have you covered.

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