the whitish slim was ammonia burn from the spike that you had. .25 is high bradda. kind of seems like the tank wanted to cycle all over again and this was all with only one meal.. that means your tank isnt stable and was not ready for fish.. your ammonia should always be 0 if you ask me or you should make sure that you keep it around 0. for it to just raise that easy and that quick just after feeding them a couple of minnows then your tank was never finished cycling in the first place. also for the future, you never use chemicals when setup and going through the process of cycling a new tank.. it alters water chemistry and the readings that it might give off when testing to see if the tank is ready. i dont understand why you would even add prime.. it is to lower nitrates and when cycling you want everything to be sky high.. thats what forms your strong bacteria and then the bacteria will take over and everything will go down. if you were doing it to speed up the process then next time use live bacteria along with the cycle but i dont recommend it. i will add it sometimes after the cycles over and i do my first real* water change.
was this a fresh cycled tank?