Maybe a sponge?

[WaterWerks]

As our tank continues to grow I have been seeing some clumps that have appeared. They appear to be a sponge. Basically want to know if they are bad for anything or anyone.
Fish and live rock only. A couple Bubble tips.

Is there anyone I can add to the tank that will potentially keep it under control?

 

[KrisReef]

Those kinds of things tend to help keep the water clean. I would be happy to have them in my fish tank.

 

[ISpeakForTheSeas]

As our tank continues to grow I have been seeing some clumps that have appeared. They appear to be a sponge. Basically want to know if they are bad for anything or anyone.
Fish and live rock only. A couple Bubble tips.

Is there anyone I can add to the tank that will potentially keep it under control?

They're not going to hurt anything in a FOWLR with a couple of nems - they will help keep the water clean.

For things that eat it:

Lots of things will eat sponges, but I don’t know if any of them (that won’t starve like nudibranchs would) are totally reef-safe - almost anything that might eat sponges are a risk to corals too (and, in some cases, inverts as well). Beyond that, not every sponge eating critter will eat every sponge, so there’s no guarantee any critter you get would eat the sponges you want them to.

Just to put this out there - the problem with using biological controls (i.e. something that eats it) with sponges is that there are a ton of different sponges, some of which look indistinguishable from others. Some of these sponges are inedible or extremely undesirable foods to some species (either because of chemical defenses* or just because of taste preferences) while being highly desirable to other species. So, even if you pull in a known sponge-eating species of fish/starfish/whatever, there's no guarantee it will eat the sponge you want it to eat. Also, many of these sponge-eating species eat other things (like coral) that you might not want them eating.

Long story short, manual removal is probably your best option for sponges until more study has been on both specific sponges and specific sponge-eaters, but you can try it if you want.

*Just as a note on the chemical defenses of sponges, many sponges produce chemicals to avoid being eaten. Some of these chemicals are more generalized, some of them are specifically anti-fish, some are specifically anti-echinoderm (starfish, urchin, etc.), etc. So, again, some things might eat one sponge but not another, and because of the whole indistinguishable thing mentioned above, the sponges that are and are not being eaten may look pretty much identical (some may be distinguished/ID'ed under microscopic investigation, others may need to be DNA tested to be distinguished/ID'ed).

Just my two cents here.

that said, if you’re really determined to try biological controls (i.e. predation) for your sponges, here are some known sponge eaters you might be able to find in the hobby:

-Angelfish (particularly large angels, from what I’ve seen)

-The pencil urchin Eucidaris tribuloides*

-Starfish (quite a few different species eat sponges, but not all of them do; aside from Aquilonastra starfish - known in the hobby as Asterina starfish - starfish have abysmal survival rates past ~8-13 months, so I’d suggest to avoid these)

-Moorish Idols (these have abysmal survival rates pretty much regardless of how long they’ve been in captivity, so I can’t recommend them either)

-Nudibranchs (they only eat like 1 to 4 specific species of sponge total, and they will not branch out beyond those species - please do not buy these, they will starve)

-Some trunkfish and (typically large) filefish reportedly eat sponges (and inverts)

I’m sure there are some other species I’ve missed (particularly fish species), but that pretty well covers the known sponge eaters.

*Info on the pencil urchin diet:

What is this? Reef safe?

Pls help I’d and lmk if safe or not

www.reef2reef.com

(As a note, the Genicanthus angels reportedly do not eat sponges).