Yes. I usually thaw enough for 2 or 3 days at a time. Fish just gobble it up, even on the third day in the fridge.

I get the 40 oz packs of mysis and just chop it up into cubes while frozen. When feeding, I just throw a couple cubes into the squeezable end of my turkey baster, connect it to the dropper end and suck up some water from my sump and let it dethaw for about 15 minutes or so. Once dethawed, I just shoot the mysis and water into a fish net and let it drain. I put the shrimp back into the turkey baster end, suck up some more water from my sump and feed using the baster.

Sounds like a lot of work, but really, it takes a minute or so to prepare. Plus, it is neat to see how the fish react when the turkey baster hits the water. My Foxface attacks the end of it and chews on it trying to get the mysis out.