What the Heck is This?

[MeatCake]

I noticed this evil looking glob thing growing in a cave section of my live rock.

Anyone know what this could be? My tank is just about 2 years old.

 

[mmorrison55]

Can you shine a flashlight on it when taking the picture? I always have a hard time finding what exactly it is the OP is trying to point out in these type of threads unless it’s circled. So much just blends together when it comes to aquarium rock and growth on them. At least for me…

If it’s the area in the middle of your pic, it may be some sort of sponge or tunicate, but it’s not clear enough to be sure.

 

[MeatCake]

Can you shine a flashlight on it when taking the picture? I always have a hard time finding what exactly it is the OP is trying to point out in these type of threads unless it’s circled. So much just blends together when it comes to aquarium rock and growth on them. At least for me…

If it’s the area in the middle of your pic, it may be some sort of sponge or tunicate, but it’s not clear enough to be sure.

 

[MeatCake]

Gemini is telling me it’s a cryptic sponge. I’m just surprised how big it is.

 

[mmorrison55]

It’s scary how big some of the critters and hitchhikers can get.

 

[Jasonak]

Im not sure but keep the lid on tight, it might crawl out in the middle of the night.......... J/K It looks like sponge to me. Nothing to stress about.

 

[EnterName]

If you are surprised by its size or sudden growth, it might actually be something to worry about. Not all sponges are harmless. They are known to produce toxins, and there are sponges (including black ones) that overgrow corals. A few years ago I had a zoa frag that I thought was glued using black two component glue, but after a while the black substance grew larger, surrounded the zoa polyps, and actually "choked" them to death. I had to nuke the entire rock in a bleach bath.

I'm not aware of any treatment for sponges that doesn't involve nuking the entire rock. Their regenerative abilities are absolutely insane (see page 5, post #82), so scraping them off won't get rid of them and might even spread them further.

Keep an eye on it, and if it doesn't stop growing even in bright areas, you might have to take action before it spreads further.

 

[vetteguy53081]

Ive heard the term black sponge and while harmless is also undesired as it can be invasive. You can often apply pressure with your thump and peel if off. If not, inject via syringe with vinegar and it will shrink

 

[MeatCake]

Thanks everyone I’ll keep an eye on it.