They get a small variety. I have regular fish flakes, sinking spirulina pellets, and blood worms, too. I've had my fish for only a few months. I'm slowly building up their "salad bar."
They sure do like the brine shrimp. The guy at the fish store even dropped a few in their molly tank to make sure before I got some. Since the loaches are so shy... and on the bottom mostly... the mollies and platies usually end up getting all of the shrimp before the loaches do.
And unless the snails have burrowed somewhere, the clowns are even better at eating snails than I thought. There were at least two in there that I figured would be too big for them to eat. But I haven't seen ANY snails. ha.