I remember afew years ago i saw on tv that cereal loses like half or more of its nutrients when you use milk, though it just loses it in the milk so if you drink the milk after, you get all the vitamins back, but i was wondering if presoaking fish food has the same effect? i know when i soak the freezedried bloodworms the water gets really brownish, and so perhaps im losing alot of the protein that bloodworms is known to have? i dump out the water in the sink after i soak the food, should i perhaps poor it back into the tank?

you're not losing the protein per se, as that is locked in the tissues of the bloodworms. what tints the water is the worms' hemoglobin that has seeped out during the freezing and thawing process.

Although your concern might have some bearing on the issue of soaking pellet food. I've always wondered about it, myself.