Different aquarium inhabitants will require different diets, and it is therefore important that you research each particular species in order to find out what, how, how much, and how often it should be fed. Some predatory fish species can, for instance, be very hard to train onto dead food and should ideally be fed live food. Other fishes will spend most of their time searching for food at the bottom of the aquarium, and a floating flake food is therefore not ideal for them, even if a few flakes eventually sink down to the bottom. If you keep other creatures than fishes, such as invertebrates or frogs, they can naturally also have very specific food requirements that might not be satisfied by traditional fish food.
When providing you fish with aquarium food, you must also keep in mind that the aquarium is a very small and limited ecosystem. Wild fish will inhabit a much more diverse environment. A predatory fish will, for instance, have access to plant material and algae in the wild, and might occasionally satisfy its need for certain vitamins by ingesting small amounts of such food types. If you place a predatory fish in a barren aquarium and feed it nothing but meaty foods, it could therefore eventually begin to suffer from malnutrition. This is however not true for all predatory fish, and many species will thrive on a diet without any herbivore parts. The same is true for herbivore fish species. Some of them will do great on a plant-only diet, while others need to supplement plants and algae with small insects, crustaceans or other types of high-protein food in order to thrive.
Most types of fish food can be placed in one of four broad categories:
- Manufactured food, such as flake food, pellets, and granular food.
- Freeze-dried food, typically smaller animals like worms and larvae that have been freeze-dried in order to prolong their shelf life.
- Frozen food, which is very similar to freeze-dried food but must be stored in a freezer and defrosted before use.
- Live food, which can be anything from tiny brine shrimp to large feeder fish.
Flake food is comprised of small, dry flakes and can be made for omnivores, herbivores, and carnivores. Flake food will usually float on the surface and then gradually sink down into mid-water. This makes flake food suitable for many fish species that feed from the surface or in mid-water, and less suitable for bottom dwellers. Bottom feeding species will instead prefer some type of sinking food, such as sinking pellets or granular food. Large fish is another category that will usually appreciate something else than flake food since they usually eat bigger items in the wild. They can, for instance, be fed pellets if you want to give them manufactured food. Live food can be purchased from fish stores, but you can also cultivate your own fish food. Cultivating your own live food is the most inexpensive method in the long run. By cultivating your own live food you can also decrease the risk of introducing potentially dangerous microorganisms to the aquarium via the live food.
There are a lot of different food types available in fish stores today ranging from flake food and pellets to frozen and freeze-dried food. Common questions among aquarists are however whether there are other foods that they could feed their fish as a treat or if there are cheaper alternatives to the sometimes expensive fish food. The truth is that there are a number of suitable fish foods that can be bought in the food sections of the grocery store ranging from lettuce to shrimps. You should however always remember that fish flakes and pellets are designed to contain everything your fish needs while the items you can buy in your grocery store isn’t This means that it becomes even more important to feed your fish a varied diet and I personally recommend that you keep pellets or flake food as an important part of the diet of your fish even if you choose to complement it with products from your grocery store.
The vegetable and seafood sections are where most suitable fish food is found in your grocery store even if there are suitable items in another part of the store as well. Exactly which items that are suitable for you fish depends on which fish you keep. You might as an example not find much suitable for a predatory fish in the vegetable section and that is why you have to know and consider your fish requirements when buying food for them.
Suitable food items in the vegetable section include lettuce, frozen peas, and Brussel sprouts. All these items are appreciated by a wide variety of fish. It is recommended that you feed your plecos and other algae eaters some of these items every once in a while. You can dip the lettuce in boiling water or freeze it before giving it to the fish to make it easier for them to eat. A rock can be used to keep the lettuce at the bottom of the tank to make it easier to reach for the algae eaters. Don’t leave any vegetable in the water for more than a couple of hours or it will start to pollute the water.
The seafood section contains many items that are suitable for predatory fish. One such food that is appreciated by most fish is frozen shrimps. The shell of the shrimp will benefit the color of the fish but might cause digestive problems in the fish. Only you can decide if you think this is a risk worth taking based on your views and the fish you keep. Other shellfish such as crabs and mussel can also make good fish food but mussels can sometimes contain a lot of toxins. Fish meat can also make good food for your fish as long as you avoid fatty fish.
I have just mentioned a few of the many food items that you can find in your grocery store that are suitable as fish food. You can experiment to find what your fish like but remember to stay away from processed, salty and fatty food. Pork as an example is too fatty to be suitable fish food and meats are overall best avoided until you get a deeper understanding of the dietary needs of your fish