I'm just starting a tank. I let the water and live sand cycle for about a week and then added live rock. Several sea stars and small crabs emerged from the rock within about 24 hours. But now, about 48 hours after that, those inverts seem to be dying. There are several other visible worms and sessile inverts still alive and well. Water temp is 77f, salinity is 1.023. Do larger hitchhiker inverts often die after introduction to a new tank? Or should I have done something differently?