Dendronephthya crab!!

[uhuru]

Can you find him? :hmm5:

This little guy has been living on my coral for several weeks now. He is beautiful but unfortunately my camera doesn't have the ability to capture the detail. He even has little red dots to help him camouflage. I don't know if he is good or bad but so far I see no signs of damage or ill effects. I am hoping he helps to clean the coral.

 

[Micromussa]

hah nice

 

[Kreeger1]

What are you feeding your dendros? Shell fish diet?

 

[stunreefer]

Very cool Mike!

I assume he was a hitchiker on it?

BTW your Dendronepthya looks absolutely fantastic!!! :thumbsup:

I've personally found little tiny crabs (1/4 - 1/2 the size of that one) on newly imported Dendrophyllia and Rhizotruchus that were bad boys. They were definitely irritating the coral, and one I saw crawl out of the mouth of a Rhizotrochus that was in bad shape; He was obviously eating it, or stealing food from the gut. Obviously just keep an eye on this guy, but he could very possibly be something like an acro crab (good boy) for your dendro!

 

[Kreeger1]

Plus one on the bad crabs on a scerlo.

 

[uhuru]

What are you feeding your dendros? Shell fish diet?

Yes, along with many other foods. It's a lot of trial and observation. FM products are really good as well. I know people say they consume mostly phytoplankton but I'm noticing better results from a more carnivorous diet, combined with FM ultra-pac. Way too early to know what really works though.

 

[uhuru]

Very cool Mike!

I assume he was a hitchiker on it?

BTW your Dendronepthya looks absolutely fantastic!!! :thumbsup:

I've personally found little tiny crabs (1/4 - 1/2 the size of that one) on newly imported Dendrophyllia and Rhizotruchus that were bad boys. They were definitely irritating the coral, and one I saw crawl out of the mouth of a Rhizotrochus that was in bad shape; He was obviously eating it, or stealing food from the gut. Obviously just keep an eye on this guy, but he could very possibly be something like an acro crab (good boy) for your dendro!

Yup, a hitchhiker! I've found other ones that I remove but this guy really looked too cute! I am keeping a close eye to see if he is causing damage. He doesn't even seem to cause the polyps to retract though when he sits right on top of them.

 

[stunreefer]

^^ That's great news ^^

Perhaps they do have a symbiotic relationship with the coral; Crab provides protection for the coral and coral provides shelter for the crab as Tetralia sp. ("acro crabs") do with Acropora sp.

 

[Micromussa]

I was interested in the little guy and did some research, he DOES have a sybiotic relationship with the coral so hes safe. ther called candy crabs or Dendronephthya Crabs

 

[uhuru]

Thanks for the info! A quick google search and I found much better photos than mine, haha! So for all the reef geeks the scientific name is Hoplophrys oatesii. There is an absolutely gorgeous picture of one at http://www.aurumspace.com/ansicht-terramare+NiedereTiere-5-as002139.htm. There is a pretty nice article at http://www.divemagazine.co.uk/news/article.asp?uan=5107.

The bad news... I've read in a few links now that these crabs take on the color of their host by eating the polyps!! What does he offer the coral in return? The exact relationship is unknown, but they have obviously evolved a specialized relationship. Does the trade off of losing some polyps give the coral something that is beneficial in return? Protection from pathogenic bacteria? Coral eating fish? I really hate to get rid of the guy, but I may have to!

 

[Micromussa]

Thanks for the info! A quick google search and I found much better photos than mine, haha! So for all the reef geeks the scientific name is Hoplophrys oatesii. There is an absolutely gorgeous picture of one at http://www.aurumspace.com/ansicht-terramare+NiedereTiere-5-as002139.htm. There is a pretty nice article at http://www.divemagazine.co.uk/news/article.asp?uan=5107.

The bad news... I've read in a few links now that these crabs take on the color of their host by eating the polyps!! What does he offer the coral in return? The exact relationship is unknown, but they have obviously evolved a specialized relationship. Does the trade off of losing some polyps give the coral something that is beneficial in return? Protection from pathogenic bacteria? Coral eating fish? I really hate to get rid of the guy, but I may have to!

Oh i didnt notice that. In either case, your coral and every dendrophythia with a crab in seem healthy. I imagine it causes minimal damage (i wouldnt want my host dead either) so he might eat a polyp or 2, but nothing noticible

 

[Kreeger1]

Just like acros, there's good crabs and bad. I've had both in my non photo corals. They do more damage then eat a polyp or 2 in a closed system. It's hard enough to feed them without a crab bothering them.
Erik

 

[uhuru]

I felt bad, but I felt worse thinking my coral polyps were being eaten, so I banished him to the sump a couple nights ago...

 

[Kreeger1]

good move

 

[uhuru]

close up shot of my dendro - sans crab

 

[Kreeger1]

Nice, I'm thinking about doing a smaller 40 ish gal non photo tank again, some of my corals from the past that I traded away or watched die due to trying to figure out there eating requirements.

 

[uhuru]

Very nice! How long did you have that tank up?

 

[Kreeger1]

Just a tad over a year, just cost to much money to feed a 360 gal display total water volume of around 500 gals. It was running 200 a month or more in food.

 

[uhuru]

I hear ya. I'm reconsidering setting up a 150g NPS (300g total volume) right now because even with this 20g tank its costing a lot of money in food. I go through Shellfish Diet and Roti-Feast like milk. May do a FOWLR at least for a year or so.

 

[Kreeger1]

my 360 became a fowlr, but i set up a 120 sps/lps tank