Today they almost all show the black spot, I've fed them very small grindal worms and they seemed to devour them!
For the microworms.. Some of them don't care, some of them do. Still alterning between frozen/non frozen/ ground up flakes, hopefully one day all of them will catch on.
I'm also working on getting another 5 gallon tank in, but that is going to have to wait until we move out of this appartment.