There is a variety of foods available for Koi on the market today. Generally speaking if you read the packaging of the food you plan to purchase it is almost like reading the back of a can of soup. You will get to know what makes up the stuff you’re about to feed your Koi.
But what about other types of food or treats? Do Koi even care for a treat or are they willing to taste test just about anything you throw in the water to them. Here’s a reality check. Would a Koi know the difference between a piece of brown bread and a piece of white bread? I doubt it and guess what?
The white bread contains bleached flour that can cause the fish harm. So the point is that just because the food is acceptable to you, and you have no trouble eating it, does not mean your fish can.
You will probably want to avoid any type of treat with a hard outer casing like corn or beans too. Your fish will not be able to digest the outer layer and this can also cause them problems. You can feed them lettuce or leafy vegetables like duckweed (as long as they are clean of pesticides) and your Koi will enjoy them.
I have heard that citrus is somewhat of a treat for Koi too. But it has been said that you should only treat them to this once per week, if you do at all.
How about live food? Yeah I know the thought of holding a squirmy earthworm above the water for a frenzied Koi isn’t the best picture I could place in your head, but people do feed them to their fish. Just clean any dirt off of them first.
Ok here’s an appetizing choice for your Koi. Young tadpoles. Yeah this is even worse to think about than earthworms for me. But apparently Koi love them, so a treat of these seems to be in order too. You can probably find all sorts of freeze dried yummies at the local pond shop too that the fish will like.
Just remember to pick a treat that is actually big enough for the size Koi you have. Daphnia fleas for instance, are great for fry, but way too small for larger adult fish. Silkworm pupae are another great treat for Koi, but should only be a very rare treat and the high fat content can cause problems with Koi and diabetes later.
The best way to think about all of this is, to feed your Koi properly. A good balanced diet with the proper amounts of protein, and vitamins is the best way to feed your fish and treats should be just that – treats. Pick the treats carefully and make sure you are giving them something that they like and will not harm them.