Is it possible to keep a group of gobies in a 75. Is it possible to mix them with blennies? I was thinking about a group of clown gobies like 10 since theyre so small or maybe mixing them with a midas blenny or algae blenny. I have about 125 of liverock and there are plenty of hiding spaces. Also how many pajama cardinals would fit in a 75 to make a pretty big school. I was thinking like 7. There are no fish in my tank right now.