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How to Feed Frozen Fish Food to Your Aquarium

Feeding only fish flakes or wafers to your aquarium fish is like the human equivalent of only eating protein bars every day. Yes, they contain a well-balanced mixture of nutritious ingredients, but wouldn’t it be nice to treat your fish to a sumptuous roast chicken dinner every once in a while? Then you should try frozen fish foods. This premium-grade fish food is packed with high-quality proteins, healthy fatty acids, and gut-loaded vitamins. After live foods, frozen foods are the next closest thing to what fish would normally eat in the wild and therefore are irresistible to picky eaters or sick animals that have decreased appetite. They are an excellent way to provide more variety and nutrition to your fish’s diet, and breeders often use them to condition their fish for spawning.

Frozen foods usually consist of whole ingredients that are flash frozen to retain as much of the original nutrients as possible and destroy any pathogens. You can purchase frozen fish food from your local fish store, pet shop, or online stores. They come conveniently packaged in individual cubes or as large frozen slabs that you can break apart into smaller pieces. In this next section, let’s take a look at the different kinds of frozen foods you can buy and which ones are best suited for your fish.

frozen bloodworms packaged in cubes

Frozen fish foods are often packaged in individual cubes for quick and easy feedings.

Different Types of Frozen Fish Foods

For meat lovers like betta fish, pufferfish, and loaches, frozen bloodworms are always a huge hit. “Bloodworms” are actually the larvae of midge flies that live in all sorts of freshwater bodies and are commonly eaten by fish, amphibians, and aquatic insects. Their bright red coloration is not caused by an artificial dye but rather naturally comes from the hemoglobin inside their bodies. You can buy frozen bloodworms in regular, jumbo, and mini sizes to best fit your fish’s preferences. Another type of worm you can try is frozen tubifex worms, which is a great food to get your corydoras and other fish to breed.

pea puffer eating frozen bloodworms

Dwarf puffers love eating frozen bloodworms, but make sure to add other foods to their diet for optimal health.

Certain fish (like goldfish, betta fish, and Apistogramma cichlids) can be prone to bloating and constipation if they consume too much protein and not enough fiber. To add more roughage into their diet, we recommend frozen brine shrimp. The Artemia brine shrimp is a 0.4-inch (1 cm) aquatic crustacean that is widely used in the aquarium hobby as fish food. Its exoskeleton is made of tough chitin, which is not readily digested by most animals, so it acts like fiber and can help your fish more easily pass their waste. For an extra boost in vitamins and natural color enhancement, you can also feed frozen spirulina brine shrimp, which consists of brine shrimp that were gut-loaded with nutrient-rich spirulina algae.

Adult Artemia brine shrimp

Fish food made out of brine shrimp and other crustaceans can help your fish’s digestive system to run more smoothly.

Nano fish and filter feeders often cannot consume larger frozen foods because they are too large to swallow and too hard to bite off pieces, so consider giving them smaller foods such as frozen daphnia and cyclops. These tiny freshwater crustaceans range from 0.02-0.2 inch (0.5-5 mm), with cyclops being slightly smaller out of the two. Not only are they a delicious source of protein, but like brine shrimp, they also have exoskeletons that help with smoother digestion. If you are raising baby fry, we highly recommend feeding frozen baby brine shrimp, which are only 450 microns in size. Baby brine shrimp are different from adult brine shrimp because they still have their yolk sacs, which are filled with healthy fats and proteins that are ideal for newborn fish.

Baby peacock gudgeon fry eating baby brine shrimp

Baby brine shrimp is one of the best foods to feed your fish fry to boost healthy growth and increase survival rate.

For larger fish, aim for frozen fish foods that contain bigger ingredients, such as mysis shrimp, krill, and silversides. If you have monster fish, you may need to start shopping at the grocery store for human-sized foods like frozen cocktail shrimp, prawns, and fish fillets. Also, certain pufferfish require hard shells in their diet to file down their ever-growing teeth, so look for frozen clams and oysters for them to crunch on.

How to Feed Frozen Fish Foods

There are several methods that are commonly used to feed frozen foods, depending on how many fish and tanks you have. The easiest way is to drop a cube (or piece of the frozen food slab) directly into the aquarium, where it quickly thaws so fish can start nibbling on it. Some people like to place the cube in a worm feeder cone to more slowly release the food and prevent the fastest or biggest fish from immediately gobbling everything up.

Worm feeder cone with frozen bloodworms

Place a cube of frozen bloodworms in a worm feeder cone to help contain the worms and make less of a mess in the aquarium.

Other fish keepers prefer to defrost the cubes in a small jar of tank water for a few minutes and then feed the liquid using a pipette or turkey baster. This technique is good for quickly feeding lots of aquariums or target feeding certain fish that get outcompeted during mealtimes. If you have picky eaters that only take live or frozen foods, we find it helpful to thaw the frozen food in a container without water and mix in a few drops of vitamin supplements to boost your fish’s immunity and brighten their colors.

Adding Vita Chemi multivitamins to frozen spirulina brine shrimp fish food

If your fish has a diet of only live and frozen foods, we recommend adding multivitamins to their food to avoid any nutrient deficiencies.

Do not to leave frozen food at room temperature for more than 30 minutes or so because then it may start to spoil and smell. Also, do not refreeze any frozen food that has already been thawed at room temperature because bacteria growth may have started and contaminated the fish food. Set a timer if needed to avoid wasting food and upsetting your family or roommates.

Frequently Asked Questions about Frozen Fish Food

How often should you feed frozen fish food? It depends on your preference and your fish’s care requirements. For typical omnivores or community fish, you can feed frozen foods anywhere from once a week to several times a week. For pufferfish, African dwarf frogs, and other picky eaters, they may refuse to eat anything except for live or frozen foods. If possible, try to vary your fish’s diet with a mix of frozen, freeze-dried, gel, live, and prepared foods (e.g., flakes and wafers) to make sure they get all the necessary nutrients they need to live a healthy and long life.

How much frozen food should I feed? This is a hard question to answer because different fish have different appetites, and some species are faster eaters than others. The two main things to look at are 1) how skinny or fat your fish are and 2) how much excess food is leftover. Ideally, your fish should have slightly rounded abdomens. If their bellies look too swollen, consider decreasing the amount of food you feed, and if their bellies are sunken in, consider increasing the portion size. Also, if your fish consistently leave lots of extra frozen food on the ground several hours after you feed them, remove the scraps and feed them less next time. For example, if you only have one betta fish, an entire cube of bloodworms is too much for it to finish in one sitting, so you may need to cut off a section of the cube to thaw out or buy a slab of bloodworms that is easier to break into smaller pieces. For more details on how much to feed your fish, read our full article here.

What if my fish refuses to eat anything but frozen foods? Some fish can get “addicted” to a certain type of frozen food (like bloodworms) and may start to reject other fish foods that they typically eat. You can train your fish to eat other foods by, for example, mixing pellets with the frozen bloodworms and feeding them together. Gradually increase the ratio of pellets to bloodworms until they are willing to eat the pellets on their own. Fasting your fish for 2-7 days may also help whet their appetite so that they are more willing to try something new.

Frozen fish foods are a fun and appetizing way to add more variation to your fish’s diet, and they feed cleanly without dissolving in the water and adding a lot of mess to your aquarium. For more ideas on how to expand your fish’s palette, read about 5 high-quality fish foods that you have to try.

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