Coralline eating Asterina

[FatherDougal]

I mentioned this in another thread but I thought it's worth posting here...

The Asterina starfish shown below eat coralline algae, so if you have this particular species of Asterina and want coralline algae you'll need to try to eradicate them first.

I've got rid of most of mine from my tank now and already (after just a couple of weeks) I'm beginning to see a dusting of coralline.

It may be that they're main action is to clean the rock surface so that coralline never gets a chance to take hold but I've seen them actively attack the coralline on new live rock that's added.

The second image tries to show that with a shot of a little piece of rock with coralline. There are pale traces before the Asterina moves in but after half an hour or so eating it's left almost nothing on the raised areas of the coralline.

 

[LockeOak]

I wouldn't mind a few of those if they clean glass

 

[TWallace]

Yeah, sign me up. Where can I purchase those?

 

[ACBlinky]

I'll third that -- I'd love a tankfull (and sumpfull) of those. Coralline is exciting at first, but many of us come to hate it -- it clogs equipment, coats the back wall (destroying that nice glossy black paint job), and generally means a lot more maintenance.

 

[TheMcs]

What did you do to get rid of them?

 

[surfjeepzx]

Yet there are some of us (me) that like the look of coraline. I have the dreaded Asterina and they can spread like wildfire. I use a siphon and a filter sock to remove them regularly. The starfish secretes a venom that kills the coraline. Anywhere they land you end up with a white spot.

The Harlequin Shrimp is the natural predator. I looked this morning at the cost involved in buying a shrimp. $26 for the shrimp and $35 to ship it. I'll just keep siphoning them out.

 

[FatherDougal]

Maybe I should stick some in a bottle and market them as PurpleDown!

I'm still catching one almost every day (by hand or by siphon) but with the numbers drastically reduced I'm seeing the first signs of coralline coming back.

They've never touched any corals as far as I know but I'd really rather have some coralline algae than a swarm of these critters.

 

[nrehman]

"it clogs equipment, coats the back wall (destroying that nice glossy black paint job)"

Asterinas seem to have munched off the krylon plastic paint which was below the coraline in my tank. Added harlequin shrimps...waiting to see results as I have hundreds of asterinas in my 210.... The wrong kind of asterinas seem to have a liking for zoas!