I have been using MicroBacterclean in my 20 gallon with fantastic results so decided to use it in my dwarf seahorse tank... big mistake. Had such a big ammonia spike in a color I never saw before, even when cycling my tanks. 8 dead but got rest into smaller tank with new water before all were gone. Glad I noticed before going to bed or all would have been wiped out. I had used it previously but since removed the sand and made it bare bottom, probably the reason...