And YES, I think that those three fish would do ok in a 75 or 90. Not that I am claiming Dr. Burgess is a genius, but he claims you can keep a tusk in a 55(I wouldn't try it), a huma in a 75(I would try it) and everyone knows you can keep a snowflake in a relatively small tank. So I think the three would be fine together in these size tanks. Just introduce the trigger last and get it a little smaller than the tusk.