Asterina starfish are reef aquarium pests that can reach plague proportions under the right conditions. Jake Adams gives some tips on how to control the little blighters.
Asterina is a broad genus of flattened starfish with wide arms. As far as we know, very few species are obligatory feeders on any one item, but they seem opportunistic feeders of almost everything, including zoanthid corals.
If there’s Asterina grazing on your zoanthids it is likely simply because you have too many. Even if you physically removed the Asterina or introduced some Harlequin shrimp to eat them, if there is an abundance of food the Asterina will reproduce faster than the rate of removal.
Cut back on feeding and ensure you have adequate flow to keep leftover food in suspension to be removed by your filter. Once you have reduced the amount of leftover, which is fuelling the growth of your Asterina, you can then add one or two Harlequins to start thinning their numbers. Then remove the offending Asterina on or near your zoanthids.
Do some Asterina removal at night and early in the morning as you will find many more out and about when the lights are off.
This item was first published in the September 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.