Do snails eat corralline & polyps?

[bllfish]

Something is happening in my tank. There are large areas on the rock that are now void of coralline algae. I HAD some blue polyps growing on one section and even up the back of the tank. About half of them are gone. I have another group of the same polys that is doing fine. I have had these for about two years. The coralline algae that was becoming almost a nuisance is also gone.
Are there any snails that could cause this?

[romunov]

Yep. There are thousands of species of snails, however, and their diets vary as well.
In my opinion, these articles are a good place to start:
The Grazing Snails, Part I - Turbo, Trochus, Astraea, and Kin (http://reefkeeping.com/issues/2004-05/rs/index.htm)
The Grazing Snails, Part II - Abalones, Limpets and Nerites (http://reefkeeping.com/issues/2004-06/rs/index.htm)
The Grazing Snails, Part III - Conchs, Ceriths, Cowries, and Columbellids (http://reefkeeping.com/issues/2004-07/rs/index.htm)

[bllfish]

Thank you romunov.

[Gawain1974]

Do you have any snails in your tank, or rather, have you added snails to your tank? Or, are you worried about hitchhikers? I'd camp out at night and go looking with a flashlight to see if you can find the culprit. Good luck! I know it's so frustrating when well-established livestock suddenly becomes dinner for someone else.

[bllfish]

Yes to all of the above. I camped out last night and saw a few snails in that area and then an emerald crab. None of them seemed to go after the polyps while I watched.
You are right, it is very frustrating - guess I will be camping out a few more nights. Hope my other stuff doesn't start disapperaring.

[Gawain1974]

Check this link out:

http://www.oregonreef.com/sub_worm.htm

He doesn't mention that his coralline was disappearing, but maybe there is some predatory worm or something. Hang in there!

[romunov]

The "culprit" is probably a snail.

I got some Neritina snails from a local reefer and they went after the coralline algae.
Luckily, they are adapt to this kind of life. :D

[bllfish]

Wow - is that thing still considered a worm - anything over 3 feet should jump to another class. I staked out my tank last night for a few hours and saw plenty of worms and other stuff but nothing went near the polyps except for a snail and an emerald crab. They did not go after the polyps though. I will have to look closer into the neritina snaills. I put a new cleanup crew in about 6 weeks ago.

[romunov]

The ones I got are from the Red Sea and I'm not sure they're sold as snails. They do lay egg capsules everywhere. I have yet to see any offspring - it don't look good, though. :( The good news is that the Stomatellas are kicking off nicely!

The search engine is overloaded atm, so I can't search, but if you feel like it, search "Ask dr. Ron" forum for string "neritina".
Some pics here (http://sloreef.com/phpBB2/viewtopic.php?t=393) as well.

[blorkiemom]

The emerald crab could be the culprit, at least for the coralline. I had one who cheerfully chewed through coralline at a rapid pace. I'd see little puff of it around his head while he ate . . .

[bllfish]

I have seen me emerald eating the coralline too. He is does seem to be hanging out in the area of the missing polyps but I have not seen him eat any. Since I have been keeping a watch he now extends both claws when I approach like he wants to give me a bear hug. Pretty fierce looking little bugger.