I also use formula 1 and 2. I think they are one of the best when it comes to flake food (i.e IMO) I've fed it to my fish in my old saltwater setup, I've fed it to my discus when I went fresh, and I'm going to feed it to my fish when I add them hopefully this weekend. I use to use the frozen stuff but too much gets lost in the tank, and also it pollutes the water too much for me even if you wash it out good. Where it is so soft from being soaked in water etc I find that when you put it into the water you get a cloud which is mostly the water and food thawed out and sometimes blood (if it is blood worms) This cloud, is basically a waste, as the fish can't eat it, and in seconds it mixes up in your water which usually accounts to the breakdown of water quality. I've watched a friend of mine feed his fish frozen brine shrimp and bloodworms and you couldn't hardly see the fish for a few seconds as a cloud covered everything. So IMO, if you aren't going to thaw the stuff out good and let some of the water in it dry out so that you can feed the tank with just the solid stuff, then you are only looking for trouble.