It's no secret that my favorite thing in my tank is my Emerald Crab. He's provided me with hours of enjoyment with his antics. For the last couple of months he has been a quiet, harmless resident in my tank - just going about his business and efficiently doing his job. He is still small, body a smidge larger than a nickle. The last few days I've noticed a change in his behavior. I don't know how long it's been going on but I took note of it shortly after I added six-ish red legged hermit crabs to my population of scarlet and blue legged ones. Since then, I've had a small blue leg and a medium sized hermit crab die. The way I find them is always the same, the shell falls off of a rock or I move it and the body floats out. I have reason to believe the crab is the one committing these terrible crimes! lol I've watched him kind of "stalk" some of the crabs and last night while watching my tank, I watched him reach out like he was trying to snap at my clown fish every time they swam by close. Anyone have any idea what could be causing this behavior? He used to be very active and we would laugh at how much and how quickly he picked things off the rocks. He doesn't seem to be doing that much any more, at least not when I'm watching. Is it possible that he's hungry? Maybe he ran out of stuff to eat on the rocks? (although looking at my rocks and my sandbed, I don't see how that's possible lol) If anyone has any suggestions, I'd appreciate it. I hate to get rid of him since he's my favorite but I can't have a serial killer on the loose!
Just a guess, but it might be he is hungry. Do you feed him anything or is he only eating what he can find in the tank. I feed mine pieces of silverside everyonce in a while to keep them from fighting each other since they are so big.
I've just been letting him eat what is in the tank. He also comes out and grabs bits of Cyclo but he's been doing that since I've started using it. Can I get silversides there? I thought that maybe he would eat the pieces of the crabs he killed but nope. not that lucky. lol
Okay, I'll try that. I sure will be glad when I move to Conway and running to the LFS is much easier! (That could be dangerous, too! haha!) Thanks for your help guys!
My wrasse does that to hermits if it gets hungry. It will pull them right out of their shell and only eats the fleshy parts. Effective little hunter!
Soon your nickle size emerald crab will turn into a huge Herculian monstrosity.......JK. I have two closer to silver dollar size and haven't noticed anything aggressive out of them. However, one of them did pinch me while I was digging around the back of the tank for a coral that had fallen.....
lol@mark I hear they can get pretty big. I've had mine for a couple of months and he hasn't grown at all but then again maybe it's because he's apparently starving and not getting what he needs from his diet of poor unsuspecting hermit crabs??? lol
I doubt very much that he is eating your crabs. I have had several emeralds in a tank at once and never fed them anything. They are savangers and mostly clean the reef. Most any crab other then hemits well wave their claws as something swims by, it is natural response to someone coming close. If your live rock has plenty of growth on it, he well be getting enough to eat and the fish poop also.
Thanks, John! I've never actually seen him on the sand. As far as I can tell he only stays on the rocks (I've spent the last couple of nights stalking him with low light). I'm not sure about the hermits. I haven't found any more dead ones, yet. Hopefully offering him some food will somehow fix the problem. Thanks for your input though - I really hope he's not.
I have had hermit shells show up empty a few days after putting them in. Water parameters fine, but maybe the were acclimated to quickly....IDK, it's kind of a mystery to me. Some live and do great and others not so much. So I know whats its like to see shells no longer moving.... Side note.......my Herculian emerald likes to grab my wall hammer in one claw and frogspawn in the other and do a few curls before completely turning them on the end......the wrong end......and he was looking right at me when he did it......
HaHa, I'm sure we could see people doing some really dumb things in and to their tanks....myself included!!
