What is gowing here?

[AngrySea]

This started a week ago and seems to be increasing in size each day. I touched it and its rubbery like.

 

[AngrySea]

I also can't spell apparently... :nerd:

 

[Mike J.]

Looks like it's a yellow sponge, Clathrina. Aquarium Invertebrates: A Look at the Sponges ? Advanced Aquarist | Aquarist Magazine and Blog

 

[Tahoe61]

Looks like it's a yellow sponge, Clathrina. Aquarium Invertebrates: A Look at the Sponges ? Advanced Aquarist | Aquarist Magazine and Blog

Nice link and good eye.

 

[joherq]

Is clathrina contagious? I recently saw a few of these sponges growing in my tank as well

 

[AngrySea]

Looks like it's a yellow sponge, Clathrina. Aquarium Invertebrates: A Look at the Sponges ? Advanced Aquarist | Aquarist Magazine and Blog

Awesome! thanks for the link. I think its the chicken liver sponge. Came out of nowhere in my nano reef 12g... its about 6 years old.