Is something eating my SPS? If so, what?

[sgrosenb]

These pictures were taken just 1 day apart. It looks like something is taking chunks out of my SPS but I'm not sure what. Does this look like something is biting them? A list of my fish is below. Any thoughts would be helpful. I have great polyp extension on most all of my SPS, although none of them are really growing. I have a few other threads that detail my SPS growth issues, but this is the first time I've seen my corals lose chunks out of them. I've never seen a fish or crab or anything go after coral, but maybe it's happening at night. Or maybe it's something else entirely....

Fish:

3x Anthias
5x Damsels
1x Yellow Tang
1x Coral Beauty
2x Flame Hawkfish
1x Helfrishi Firefish
2x Picasso Clowns
1x Bengi Cardinalfish

Crabs:
A ton of them. Mostly emerald but some other reddish/maroon ones too. Some of them are BIG.

Thanks for any help!

 

[Charlie’s Frags]

I’ll never put an angel fish in my sps tank.

 

[DivingTheWorld]

Frankly it just looks like a turbo snail might have scraped it. But I agree, Angels munch acros. Usually people who have them have huge tanks with tons of corals so a few bites here and there don’t matter. You mentioned crabs too and I’ve caught emeralds picking at acros. Could be a crab.

 

[Graffiti Spot]

I agree with the above. The coral beauty is a polyp nipper and won’t snap off skeleton like that. Large angels will but they normally go for the tips of the branches. And the smaller angels that have more round lips will do some damage to the whole coral by mouthing at it to get them to slime up. I had a multicolor favorite one acro and kill it slowly like this. I would worry about the coral beauty for this. Maybe a large Mexican turbo or a crab would do this.

 

[IslandLifeReef]

I think the Coral Angle has been voted off the island!!

 

[sgrosenb]

@Pedoconfuego @DivingTheWorld @Chaswood79 Thanks guys for the feedback. One more piece of evidence that might help? The top of the coral also got nipped off, which to my takes snails and crabs out of the picture. Any thoughts?

 

[TexasTodd]

I'd bet a crab.

 

[CCauthers]

Ive had trubos and urchins scrape up against the base and tear away parts just like that on the bottom, I would keep an eye on it

 

[ScottR]

Must be a crab. Check in with a light at night.

 

[Cell]

A ton of mostly emerald crabs? There is your main culprit. Roughly how many emeralds is a ton?

 

[sgrosenb]

I'd say probably 6-10 somewhere around there. I got them to take care of my bubble algae, which they did a mighty fine job with. But apparently there's a big downside to that... Bummer. Not sure if I can successfully get them all out but I can give it a shot

 

[Cell]

I'd never put more than 1 emerald per 50 gallons or so.

 

[sgrosenb]

Oops... That's not good. You think if I keep 2 or 3 of them in there, they'll lay off the corals? Or is no emerald crab safe?

 

[Cell]

Emerald crabs are hit or miss. You can find a well behaved one and keep it well fed and it will be fine. Or it may get hungry and find fleshy coral appetizing. Generally, I like to think as long as it is well fed, then it has no reason to pick at coral.

 

[DivingTheWorld]

[QUOTE="sgrosenb, post: 7816143, member: 10674]Thanks guys for the feedback. One more piece of evidence that might help? The top of the coral also got nipped off, which to my takes snails and crabs out of the picture. Any thoughts?[/QUOTE]

Not sure about that one. Angel would be my best guess. I agree the top wouldn’t be crabs or snails.

 

[A Reef Creation]

I’ve had rouge Emerald crabs eat Acropora before. I’ve to witness it first hand. The crab would climb on top of the acro and crush the tip and pull out the fleshy polyp to eat. I’ve mainly seen large males do this. The ones with big claws. I tend to just put females in my reefs when I can.
The slice angled cut in your second photo set would make me think it’s an Emerald 100%. They usually do it at night. I would find the one that was doing it and usually leave the rest in the tank and not have problems again.

 

[Charlie’s Frags]

I’ll never put an angel fish in my sps tank.

I’ll never put an emerald crab in my sps tank

 

[sgrosenb]

haha. welp... looks like i have some crab huntin' to do

 

[Leemcg]

My first thought was the angel. But I can’t see a coral beauty getting that big of a chunk from the top, polyp yes, chunk no. I’d watch at night and see if you can catch the crab in the act. Too many crabs to start with, but you definitely want to get the right one out first, that has developed a taste for that coral, before reducing there numbers.

 

[sgrosenb]

Sounds good. I looked back at my order and I ordered 6 emerald crabs, so I'm going to attempt to get 3 or 4 out and donate to my LFS.