Found under a rock

[RyKenna]

Idk what this is or what should I do with it

 

[KrisReef]

Sponge or bryozoan. I would leave it be. Healthy diversity in the aquarium.

 

[RyKenna]

Sponge or bryozoan. I would leave it be. Healthy diversity in the aquarium.

How did I get it do they just randomly grow on rocks

 

[KrisReef]

How did I get it do they just randomly grow on rocks

I found one growing on a rock that was in a bucket outside my garage for at least a year recently, and I don’t think it was “there” when I put the rocks outside. They hitchhike as smaller chunks and grow if they get enough food, probably bacteria(?) from their surroundings.

They likely release stuff into the environment that feeds coral but that is a guess based upon what little I know about sponges who live in a similar niche.

 

[ISpeakForTheSeas]

How did I get it do they just randomly grow on rocks

It's a sponge, and it's harmless. They don't just spontaneously appear, but it may seem like they do.

They either settle there as tiny larvae and grow like any other animal/plant, or a piece falls off of a sponge and regrows into a full sponge of its own (some sponges can regrow from single cells, so you would literally need a decent microscope just to see them as they start regrowing).

 

[Subsea]

How did I get it do they just randomly grow on rocks

Where did this rock come from? How did you cycle your tank.

I use sponges for natural filtration. In addittion to phytoplankton, sponges eat bacteria, viruses and free swimming parasites like ick. I am fairly certain that tube anemone & sea apples eat free swimming parasites as well.