| Greg, I do not have the direct knowledge to answer your question; but I do believe the greatest threats to any fish fry are (1) the presence of parasites and (2)absence of appropriately minute food. They are too delicate to endure an infestation or lack of nutrition. Most parasites throw young/eggs into the water environment. I think it always the better practice not to breed fish known to have parasites and to avoid spawning quarters with parasites. In regard to koi, I think the leading Japanese breeders follow rather sterile processes in spawning, but I'll leave to others with more direct current knowledge to comment further. |