Asterinas freak ppl out bc they appear to be munching on coral where in fact they are only eating the dead tissue off a coral.
Problem with asterinas is their population can EXPLODE literally in a week. NOT fun in the AM to first put your eyes on your morning tank and see 500-800 asterinas all over the glass, everywhere.
No one really knows the conditions conducive to their EXPLOSION, but when it happens it ruins the look of your tank.
To even have a shot at controlling them, you have to manually pull them out by hand. Couple years back, i would manually remove 200-300 every other day and they kept coming. Then one day, it all stopped.