Fishman1995,
Most fish live with diseases such as ich and show no signs of it. When something stresses the fish (poor water quality is a typical stresser), this will lower the immune response to the ich. That is how a tank that has been set up and nothing added to it in years can SUDDENLY develop a case of ich.
If the fry were kept in the net suspended in a tank that had a fish in the tank, that would have been stressful to the fry. Fish will try to eat fry through the net. Since fry do not have fully developed swim bladders when very young, they sink to the bottom when they do not actively swim. This causes them to rest ON something (the bottom of the net, any gravel or plant in the net with them, etc.).
You can feed your fish whatever you want, its your tank and your fish. I was just pointing out that its not the wisest of things to do. Even a fish that died of 'natural causes' can carry disease. If you are going to feed your fish other fish, its best to use a live (hopefully undiseased) fish, or a fish that you have just killed for the purpose of feeding.
Just my 2cents.
OC