No way. That is only 15gallons. A rectangular tank of that size can't have clown loaches or most types of plec. What is the 'snakey one'? And as littlefishy said, clown loaches get v. big, and common plecs get up to over a foot long. And I'd be a bit doubtful about 3spot gouramis, too. I'd only say keep smaller species like honey or dwarf in a 15g.