Help Id please

[alucard102k1]

have this dark purple substance on under rock and it looks a little hairy.

 

[BostonReefer300]

Hard to tell in that lighting, but could be cyano

 

[alucard102k1]

Hard to tell in that lighting, but could be cyano

It's dark purple, doesn't look like cyano

 

[Garia666]

Sponge

 

[BostonReefer300]

If it was under the rock and, in particular if there was still good flow around that spot, then I'd agree with @Garia666 that it's probably sponge. If it feels crunchy, it's definitely sponge. Some people claim sponges are really bad for coral due to chemical warfare. Others think they're great filter feeders that clean the water column. Still others think they're neither good nor bad. You'll have to research it to decide for yourself. I personally don't have an opinion on them myself yet

 

[alucard102k1]

If it was under the rock and, in particular if there was still good flow around that spot, then I'd agree with @Garia666 that it's probably sponge. If it feels crunchy, it's definitely sponge. Some people claim sponges are really bad for coral due to chemical warfare. Others think they're great filter feeders that clean the water column. Still others think they're neither good nor bad. You'll have to research it to decide for yourself. I personally don't have an opinion on them myself yet

thanks.

 

[vetteguy53081]

Black sponge. Not desirable due to toxicity. Taje out of tank and into a container wiith tank water and scrub off