Originally Posted by
MikeM
The comment about high fiber got my attention. We do not see much discussion about fiber in a koi diet. Some fiber is good, just as for other animal diets. High fiber contributes to increased fines in the water. It may seem that high fiber is a negative. However, fiber in most pellet foods is replacing carbohydrate. Some foods will use such ingredients as rice hulls and bran. While these do have some nutritional content, we often think of them as 'cheap filler'. Some foods do use high fiber ingredients just to lower costs. Some, however, have a more thoughtful purpose, using a high fiber ingredient to reduce carbs.
Some of the inexpensive fish foods not specifically designed for koi have a moderate protein level and high carbohydrate level. These can lead to chubby koi, fat abdomens as if filled with eggs, and an overall stubby sort of appearance compared to the sleek spindle shape desired for koi. The koi can be healthy in the sense that they do not have parasites, sores or visible maladies; but, like an overweight person who suffers from malnutrition or diabetes, there can be adverse impacts on the organs leading to premature deaths. This may not be very material to the fishkeeper, since most koi die from one cause or another long before the adverse impacts of fatty liver, etc. are noticed. Far more koi should live to be 15 or 20 or 30 years old than do. The high fiber replacement of carbohydrate can actually be beneficial. ....I think most folks feed more than the koi need anyway.