micro brittle stars will eat food that your fish miss. if you dont have fish, and dont feed the tank, i THINK the brittle stars would survive off pods. but 2 brittles will eventualy become 200 brittles.
i caught a large mini brittle starfish and put it into a cup. 20 minutes later i had 4 super tiny but fully formed brittle starfish babys. aparently they form inside the central disk and are released.