Recommendations: Small, peaceful, interesting sponge eater?

taricha · Feb 11, 2018

I'm not looking for a fish to fix my problems, I just think it might be cool to have that additional natural food web interaction in my tank.
I think I'm figuring out how to grow sponges pretty well. I have at least half dozen varieties established and growing in the tank - some getting big. If I succeed in ramping up the sponge growth and my new cryptic zone starts getting well colonized by sponges (as a protected area that the sponges can re-seed the display from), then I'd like to have a cool fish that would graze on sponges.
Requirements:

needs to be chill. Everything else in my tank is peaceful - gobies, blennies, dartfish, pajamas, and some are spawning.
not a coral eater. Fine to nip a zoa or sps every now and then, but not eat colonies. Also Gorgonians. I love my gorgs too.
small - 70 gal tank.

Other considerations:

should be a cool fish. Like I said, this isn't to solve a problem, it's to add interest.
Carribbean or similar would be a plus. Since that's where most of my hitchhiker sponges came from.
I'm also open to out-of-the-box suggestions. Saw a claim that a linckia starfish may need sponges and hence its poor survival most of the time.

Cherub Angel? Butterfly of some sort?
I'm not a super experienced fish guy. I'm going off info here:
The Pygmy Angelfishes - James Fatherree
Aquarium Fish: Butterflyfish - Francesco Ricciardi (there seems to be much dissent to this author's opinions)

Suggestions and good reading material?

K. Steven · Feb 11, 2018

I've always liked the look and personality of C. argi.

taricha · Feb 11, 2018

Do centropyge argi actually eat sponges?
I was looking at a source on their diet in the wild and it was one of the only angels that they didn't find sponge in their diet.

K. Steven · Feb 11, 2018

taricha said:
Do centropyge argi actually eat sponges?
I was looking at a source on their diet in the wild and it was one of the only angels that they didn't find sponge in their diet.

I've seen them eat sponges off live rock, but I'm not sure if they show species preferences. It could also just be their inquisitive nature to taste textured epifauna.

Jesterrace · Feb 12, 2018

The Cherubfish is beautiful, but they can be aggressive and I sure wouldn't want to pair one with the biggest cowards in the saltwater industry *cough* dartfish *cough*

eatbreakfast · Feb 12, 2018

Angels and butterflies will eat sponge, but most butterflies that eat sponge will also try corals.

I agree that argi is a little aggressive for what you are looking for.

taricha · Feb 12, 2018

Thanks @eatbreakfast @Jesterrace. I accept the possibility that the fish I'm looking for may not exist.
Sponges are much less nutritious than corals, so fish that love sponges but won't eat corals don't make much sense.

lion king · Feb 12, 2018

The Cherub angel is a cute, fun fish; I kept one in a reef that seemed to be pretty reef safe as I could tell. But the dwarf angels don't seem to be the spongivores as the large angels. As stated above, if you get a fish that will graze on your sponges, they will likely give some of your corals a taste as well.

taricha · Feb 12, 2018

Opinions on rock beauty angels?

Maritimer · Feb 12, 2018

Challenging, and probably significantly bigger than what you're looking for.

Which adds up to 'bout pretty much all I know about them.

They used to be considered one of those fish best left in the sea, but from what I have heard, they seem to do better in aquaria these days than they used to.

~Bruce