Pink Blob Sponge?

Ok, I have a hitchhiker, picked up some small zoa frags and was anchoring them around my tank and the next day I realized that I brought something else home as well.

If you look right in the center of the picture you can see a pink arm looking thing curling under.

Whaddaya think boys and girls? Sponge?

 

I'd say it's a sponge. What kind of feel does it have to it? Squishy at all?

 

I've not poked it yet....If I come back with a bloody nub I'm blaming you!

 

yes, it's squishy.

 

Then it's pretty well definitely a sponge.

 

Is it good / bad / indifferent? How are they, if at all, beneficial?

 

They eat planktonic algae in the tank, acting somewhat like a protein skimmer. This one isn't big enough, at all, to be a significant difference in that manner. That's pretty much all they do, though.

A few can overgrow corals, or eat crustaceans, but that's not really common.

 

Cool, appreciate the info.

Out of curiosity, how do they catch crustaceans? Where is the mouth?

 

Ever seen how a coral puts out minestral filaments when it's eating another nearby coral?

 

No, not to this point but I'm keen to know what to look for now.