Because of a long and complicated line of cause and effect, the protein level of the food turns out to be the major contributor to the health of a fish. The more protein, the clearer the water. The clearer the water the healthier the fish. When I buy commercial food I always buy the highest protein food I can find, regardless of the species of fish.
Note the labeling food as specific to a certain type of fish i.e. “goldfish food” is just a meaningless marketing ploy. Fish food is fish food. And the high protein recommendation applies regardless of the type of fish.
The ingredients in fish food turn out to be relatively unimportant DIRECTLY to the health of the fish. Almost any fish food is just fine for almost all fish. What is important is the amount of fish food. Only feed the volume of one fish eyeball per day per fish (six fish = six eyeballs worth of dry food). Overfeeding is probably the most common cause of fish deaths among beginners.
Fish Food in a Little More Depth
The amount of fish food to add used to be very important in the hobby. When I started in the hobby many years ago all the small guides I bought in my fish store, the small “Your First Aquarium” books, emphasized that the newcomer needed to only add what food fish could consume in one minute once a day. They emphasized that overfeeding killed fish.
The guides I see online now don’t make that caution. Since this is extremely important I find that somewhat confusing. If I hadn’t had that caution drilled into me early I think I would have lost a lot of fish and probably not stayed in the hobby.
The biggest mistake beginners do is to over-feed their fish. The directions on the food are ridiculous. “two to three times a day an amount they can eat in two minutes” is WAY too much food. Fish are cold-blooded creatures and only need small amounts of food once a day. They should be fed an amount equal to one fish eyeball once a day. This is not a lot of food!
Also, note that if one feeds fish something other than commercial food one has to take into account that commercial food has little moisture in it while something like shrimp from the freezer or frozen fish filets have 80% water in them. So the amount of shrimp and fish filet one can feed is five times that of the commercial dry food. If feeding shrimp or fish filet do five eyeballs per day.
Uneaten food in the aquarium produces bacteria. Bacteria produce toxins. And those toxins can kill fish. For more on the amount of fish food to feed, go to this link:
What is not important is what food to feed. Most commercial food made for fish today is excellent, so it is difficult to go wrong when feeding fish, contrary to popular mythology. This applies to the direct effect of fish food on the health of the fish and does not apply to the indirect effect of the protein level in the fish food.
The only trick that most experienced fishkeepers use is that they feed ALL fish some roughage at least once a week. That roughage can be whole vegetables like “zucchini a la fork” or it can be the chitin from something like dried krill. Like humans, fish seem to need roughage to keep the digestive tract healthy.
There are a huge number of myths parroted around social media about fish foods. Some of these myths are:
- The type of food fed to fish is directly critical to success in the hobby.
- Different types of fish (herbivores, carnivores) can’t be kept together because they require different foods.
- Feed fish only what they can consume in five minutes (or two minutes three times a day).
- Mbuna get “Malawi bloat” when fed high protein food.
- “Just like us, fish enjoy a varied diet”.
- Live foods are the best foods for tropical fish.
- Animal protein has an inferior nutritional content compared to plant protein.
- There is such a thing as “high quality” and “low quality” protein.
- Chicken, tilapia, and beef are bad foods for fish.
- Fat is bad in fish food
- Krill, bloodworms, and tubifex worms are bad for fish.
- Mbuna are herbivores and eat only plants.
- Lots of fish require live foods.
- Vitamins are required to have good fish colors.
- Wheat, corn, rice, oats, and potatoes are good foods for herbivore fish.
- Fish will starve before eating a fish food they don’t “like”.
For more on fish food you can click on this link: