Crab and Sps Question?

[pnavarro170]

i had purchased 4 crabs, the 2 bigger ones are brown and pink looking. i thought they were all emerald crabs that should be green obviously.

now a couple of my sps small colonies have tips kinda broken off, with discoloration. they dont look just discolored they look broken off. are these crabs the issue ??? whats going on here ???

 

[psuedopimp]

pictures of the crabs? and the damage

 

[pnavarro170]

ill try a bit later for sure on pics. close ups kinda stink but we shall see.

 

[pnavarro170]

heres one, i moved it to my 20 gallon, hope you can see the clean break offs of the tips

heres the other, i have a small frag from this same frag doing well in the tank, and again tips are cut clean off.

heres one of the crazy crabs cant find the other right now.

 

[ryan_paskadi]

Emerald Crabs go by the scientific name Mithrax sculptus. That genus and species is known to come in colors other than green.

This is a Mithrax sculptus crab, but the common name would be Ruby Red Mithrax Crab.

 

[ryan_paskadi]

As for the tips of your sps.... well yes... all crabs are opportunistic omnivores. These guys eat, nuisance bubble algea, corraline algae, snails, and tips of your corals. If you do not have bubble algae then you might have problems.


"Overall, this can be a good scavenger for your tank. Use caution if you have a reef tank with snails and corals. They may eat or nip at coral polyps. Fish only setups should have no problems with keeping these emerald crabs."
http://www.fishlore.com/profile-emeraldcrab.htm

 

[pnavarro170]

even if its a red mithrax crab, those are suppose to be reef safe ????

 

[reefer4ever]

I would justlike to say that the first coral is amazing! hope your corals do great!

 

[pnavarro170]

that first coral was more amazing, tips are blue. well suppose to be. and it should recover.

 

[mistaflicksta]

hey Ive seen that ric before! lol!

 

[pnavarro170]

i got the green one in the 20, the other 2 in the 90, but might put them all in the 20, i keep it a bit warmer and less flow makes em open up a bit more.

 

[pnavarro170]

k well i was able to grab 2 of the crabs, small green emerald and that on redish, next putting those 2 frags back in the main tank. ill keep an eye out for the other 2, another green and a brown one.

Any one want some Crabs ??? haha

 

[deehz]

Pedro,
It might not be the crabs that you got that's nibbling at the corals. I do agree with Ryan that crabs are opportunistic eaters.

However, don't you also have an angel fish, trigger, and a puffer fish in the tank. All of these fish "maybe reef safe (you may have been told this) but most online vendors will tell you to add with "caution". They maybe turning onto your frags without you even knowing it. I would due some research on your fish first. That's what I had to do when I saw my sps had nibble bites on it, just like yours. Did research on the fish I suspected and it turned out that the fish was not reef safe--it is a coris wrasse (well it said to add with caution). I was told "they were" reef safe. Found out they love small hermits, snails, and sps corals. Find out who the "perpetrator"'is first so no one else gets harmed. Then make the appropriate decision to rehome the culprit safely. Good luck!

 

[mistaflicksta]

yep it might be the fish. I keep an eye on my flame angel. he keeps circleing the clams. he looks at them intensely but has not touched them yet. hope it stays that way because it is a pain in the *** trying to get a fish out of the tank without tearing the tank apart, I am a little cautious with the angel because I had a cleaner wrasse that started that behaviour and finally decided to nip @ the clams, leading me to taking the tank apart to get him out. thats how much I like my clams. Come to think of it I might get rid of all of my coral and start a clam tank! just kidding. but I would like more clams in my tank

 

[pnavarro170]

actually, i had lost the angel when my salt was off the charts, and i was able to save and get trigger out of there before he died and i was planning to replace him with another male down the line, never had a puffer.

only fish in there are 7 chromis, melanurus and leapord wrasse, zebra barred dartfish, 2 other gobies, and a purple tang right now.

 

[pnavarro170]

and yeah i thought about that too, but none of these fish have ever looked at a coral, and these 2 frags ive had for a while and were growing till right after i added the 4 crabs, and a handfull of little hermit crabs and one large blue legged hermit. so its weird, if it was just discoloration, or all the rest werent looking perfect and growing id be less confused.

 

[mistaflicksta]

Then it might be the crabs, Large crabs cause alot of problems. I usually get rid of my hermits before they get big enough to fit in a big turbo shell.

 

[ryan_paskadi]

Reef Safe is a very subjective term. These crabs can be reef safe they can also be very bad. Some people have luck with all manor of fish and inverts that are typically not so reef safe. Usually the trick is keeping them fed. I do not think these crabs prefer to eat corals, but if other food supply is low they start munching on less desirable fare.

I would get rid of the red ones, and the larger ones. Keep the smallest green one and you might find that its not an issue.

 

[pnavarro170]

thanks guys, just need to get one last large one out, i see him, but hes playing mind games with me. i was under the impression they were totally reef safe. anyways, sps back in the main tank, ill keep ya updated.

 

[deehz]

Reef Safe is a very subjective term. These crabs can be reef safe they can also be very bad. Some people have luck with all manor of fish and inverts that are typically not so reef safe. Usually the trick is keeping them fed.

+1

thanks guys, just need to get one last large one out, i see him, but hes playing mind games with me. i was under the impression they were totally reef safe. anyways, sps back in the main tank, ill keep ya updated.

I agree Pedro, put the sps back in the main tank and see what happens. It could very well be that corals are either: being nibbled by crabs, fish (leopard/melanurus wrasse?), alk/mag/ca are low causing discoloration, stability of water (swings in PH and SG). These could all very well be causes.

SPS require good, stable water quality with adequate flow. They are awesome corals with beautiful colors. The downside is that they are very temperamental and can be very hard to keep. If they do not like the water or the environment they are in, they just go. Good luck.