What is this Coral?

[kirkfish]

I had this show up in my tank about 2 years ago. It's not fond of light and grows really slow. I think it's a Coral, but I'm not sure. Does anyone know what it is?

 

[kfisc]

Looks like a sponge to me- usually a sign your tank is healthy.

 

[kharmaguru]

Looks like a sponge to me- usually a sign your tank is healthy.

Could also be some type of tunicate.

 

[reefing102]

Agree either sponge or tunicate. They will come and go/shrink and grow depending a lot on your nutrients in the tank. If a tunicate, it won’t get very big from my experience. Sponge…they can generally cover a lot of ground given the right conditions but usually not anything impactful unless it’s a photosynthetic (which that does not appear to be)