Fish Injury!!!

I just set up a 55 gallon saltwater tank. i put in all the live rock that I wanted and let the tank cycle for about a month or so. All the water parameters are good and the ammonia, nitrite, and nitrate are at 0. I notice that I had a stow away in the rocks, some kind of crab that I cannot identify. I recently introduced my first fish, a royal gramma. It is doing really well except for the fact that it is missing half of his tail. It was intact when I put it in there and now its cut in half. It is a very clean cut it isn't jagged or anything and it does not look like tail rot. Could the crab have got a hold of him? My main concern is if its tail will grow back and I if i should place him back into the quarantine tank. Any info would be greatly appreciated.

 

If there is nothing else in the tank besides the fish, the rock and the crab it would be safe to assume the crab is the culprit. The tail should grow back in time. Get that crab out of there ASAP.

Good luck.

 

You didn't mention your pH. I just put a wrasse in QT and his tail went to heck...turned out my pH was off.
Good luck w/ the gramma -- that was my first marine fish as well and it's a great choice.

 

Would abnormal PH leave such a clean cut?

 

Get the crab out.. If you have a low PH it just mean the water was depleted of it's Buffer then again it also depends on what time of day you test PH or look at the monitor/meter.. I'd Never use live rock unless I set it out on a tarp for a few hrs to allow the hiding crabs and mantis shrimp and all of what ever is in there to get out.

 

I would suspect water quality issues to be the culprit. A crab will take a chuck out of a fish but that's it. It is likely this crab will some day become a pest but unless it is quite big now I would not suspect it was the culprit.

Check you water parameters daily. ensure the food you are using is high quality. Remember this fish has had a very long and stressful trip to finally get to your tank. It will take some time but if everything is in line with your tank the fish will be OK

J

 

I had a couple stowaway crabs in my live rock when I set up my 75 gallon tank, These crabs made quick work out of killing 2 fire fish. they took a nice clean cut in one of them on it's stomach. The second fish had a piece or it's dorsal fin cut completely off, and then it had a similar injury as the first one but this time it punctured the swim bladder of the fish and then it eventually died. So I would agree with Tangster Get the crab out of your tank... John

 

WOW John if you hadn't have said it I wouldn't have believed it. I always thought the crab theory was a mith and fish were just to fast. Learn something new every day

J

 

After a hell of a time capturing the stowaways I took them to my LFS and we put them in a tank with a Trigger fish and I could not believe what one of the crabs did, When the Trigger tried to eat it the crab latched on to the triggers face and wouldn't let go, Eventually the trigger got it off and ate it, but that just amazed me how vicious those crabs were.