Can someone ID this purple spikey algae looking stuff on my live rock?

[az_joe]

Hi. I have a spot of dark purple growing on my rock. It is covered in spines. Not sure what it is. Can anyone help?

 

[Timfish]

It's a combination of small tube worms and a purple sponge growing over them. If it is black under white light it might be teh one sponge I would remove (blue light can make a black sponge look purple). I have black sponges that at the least are not harmful to corals and probably beneficial but there is one black species that will encrust over corals and kill them. If it is a pruple sponge in white light it's beneficial. But if it is a black sponge and looks like the one in the pics in this article with the star shaped osculum or siphon pores and is also fast growing it would be best to get rid of it.

https://www.researchgate.net/publication/257398076_The_coral-killing_sponge_Terpios_hoshinota_invades_Indonesia

 

[az_joe]

Thanks for the info. It definitely looks black under pure white light so I'll get rid of it.

 

[ackshee]

Wow! Super cool.

 

[ISpeakForTheSeas]

Assuming those aren't tube worms sticking out of the sponge and that that's just the sponge's actual texture, my thought/guess would be a Darwinellid sponge (taxonomic family Darwinellidae), possibly a Chelonaplysilla species (though I haven't looked into these sponges enough yet to say for certain).