Your tank is already over-stocked so I can't recommend adding anything
. Maybe if some of the fish were re-homed (and then, yeah, I'd add tiger barbs).
Clown loaches are indeed schooling fish but they get WAY too large for a 40-gallon. Since you'll have to upgrade the loach to a larger tank later anyways, you might as well wait to fill out the school.
Clown loaches are indeed schooling fish but they get WAY too large for a 40-gallon. Since you'll have to upgrade the loach to a larger tank later anyways, you might as well wait to fill out the school.