It seems for every type of fish there is a fish food, goldfish food, cichlid food, sinking pellets, catfish pellets, algae wafers, and that’s before you get to the various types of frozen food, live foods and supplements.
So what do we need to feed our fish?
Whilst some fish like goldfish and koi have been breed in ponds and tanks for hundreds of years, others have only come into the hobby in more recent times. Many species are still wild caught, whilst others are only a few generations from their wild ancestors.
The majority of species come from the Amazonian rain forests and the surrounding areas, where they have evolved to like in a very specific niche. Specific water parameters, temperature and foods, and the closer we can replicate these conditions the healthier our fish will be.
So what is a natural diet? What foods would your fish be able to get and eat if it were in the wild? In the rainforests and jungles that many our fish come from vegetation, fruit and vegetables all fall into the water and can be eaten. Algae grows on the rocks, insects lay their larvae in the water and for many species other fish provide the ideal food stuff. But there is little chance of anyone providing these in the correct amounts, especially if you have a mixed community of fish.
Macro nutrients are the big things we need to worry about, carbohydrates, fat, protein and fibre etc., whereas micronutrients are the vitamins and minerals our fish need, calcium, magnesium, sodium etc.
Food manufacturers research the exact needs of the fish and produce a good solid balanced diet. The cheaper foods can contain large amounts of fillers that may foul the water and not be as healthy for your fish, so aim for one of the better quality brands.
Most professional or hobbyist breeder base their fish’s diet around home grown or homemade foods, depending on the species of fish. But there is nothing wrong with using a selection of commercially prepared foods. Live cultures and live foods are also a good staple.
There are a number of different options when it comes to growing your own live food. Daphnia, Glass worm, Banana Worm, Grindle Worm, Micro Worm and Vinegar eels can all be purchased as starter kits and grown as cultures and feed to the fish daily. Brine shrimp eggs can be purchased and hatched as food in small amounts. For larger fish Earth Worms can be grown in wormeries. These larger live foods can be fed food containing vitamin powders and nutrients which will then be eaten by the fish. Snails are a popular treat for loaches, and can be garden snails collected from a safe, pesticide free location.
A favourite of discus keepers the main ingredient is raw heart, normally with vegetables such as spinach, garlic and other foods, and added vitamins and minerals. The main objection to this is that wild discus don’t normally find whole cow, pig or turkey hearts floating down the Amazon. Whilst this is true the macronutrients of this mix in theory should replicate the foods they would eat in the wild. Many discus and other cichlid breeders feed beef heart as the majority of the food, although there has been a recent change to pork and turkey heart for some breeders.
One of the risks of feeding fish to fish is the risk that the food fish, whether dead or alive is carrying parasites or disease that can be passed on to your fish. For this reason, as well as the obvious animal welfare implications it is not advisable to feed live fish. Feeding commercially caught and prepared fish can be safer as the period in the freezer should have killed all the parasites.
Many of the fish in your tank need a significant proportion of vegetables in their diet. Even those that are mostly carnivorous will benefit from the extra fibre once in a while.
It’s always better to choose fresh and organic where possible and thoroughly wash them before use.
Courgette/Zucchini/Marrow; slice and deseed, blanch by pouring over boiling water and leaving it to cool, squeeze out the excess water and drop in the tank. Alternatively slice and deseed then use something heavy to weigh it down, screwcumbers are available on line to keep your fruit down on the floor of the tank for them to eat. Plecs, Loaches and catfish tend to go mad for this.
Mushrooms; wash peel and put in your tank, it’s worth weighing it down, again plecs love these, as do many guppies and other livebearers.
Peas: deshell and drop into the tank, this can be used to prevent constipation. Which can be fatal in some species including goldfish
Melon; a favourite with some loach species deseed and weigh down.
Carrots/Cauliflower stalks/Broccoli stalks/shredded greens; can all be fed, they will need weighing down
Garlic; whole cloves of garlic can be floated in the tank, this is said to help reduce nitrate, and is a well know antiseptic and often added to prepared foods.
Some fish are various feeders and will outcompete tank mates. Bottom feeders are often left out as surface and mid water feeders eat all the food before it hits the bottom. In this case it’s worth target feeding this fish a few times a week. This can be done using a turkey baster or similar to squirt the food closer to them, or long feeding tongs to offer solid foods.
In general you should feed only as much as your fish can eat in 3 minutes, and then remove all uneaten food. But if you have nocturnal fish then they may not come out to eat until after lights out, meaning you need to leave the food out until a few hours after lights out. In a healthy tank with good filtration some food in the tank overnight shouldn’t adversely affect the water parameters.