blitzen- Depending on how they are raised and the species of the particular fish, it often happens that it is necessary to feed them live food as a staple diet. You could always try to accomodate them to different foods, but is isnt always successful. I wouldnt worry about it at all, especially if you are overseeing the breeding yourself. The one assertion that I have always detested is that "live foods are bad for fish." There is always risk involved in feeding live food like guppies, I do not deny that. But that risk is easily minimized, and you can work the nutrition and vitamin element either into the bred fish themselves or by attempting to supply pellets. I certainly wouldnt advocate going out to a chain pet store and buying feeder fish, and I believe that places such as walmart, petsmart, etc..(as well as irresponsible pirvately-owned stores) have done an incredible diservice to the percieved safety of live foods. While your strategy of home bredding is probably the best, it is also good to find a store that you can trust, if possible. Even while I breed my own feeders, I have continued to purchase them from my local dealer, and in my 10 years of experience with him I have yet to encounter a health problem. It is likely the case that many people fail to acknowledge the importance of feeder quality, and it is also difficult to detect infirmities in many cases. But, overall, I would argue that live foods are an excellent option when treated with the appropriate discretion. I think you will be fine.