Another clue to the tradgedy: Last week I went switched light hoods and the HOB filter lid was in the way so I removed it, and lo and behold the biowheel wasn't spinning at all even though the filter was still flowing fine. I tore the whole thing apart and cleaned it all. I'll keep an eye on it, not sure if that had quit at the time or not.
Anyway, will he eat bloodworms? How long should you let him go when trying to wean him off minnows? It's been 3 days and I'm getting worried I'll feed him tomorrow unless someone says its okay to go a bit longer. He won't touch the frozen bloodworms yet.