Mean Hermit Crab!!!
 

So when I established my tank 1 year and a half ago when I bought the first bit of my live rock a tiny little hermit crab tagged along. I noticed he wasn't blue legged but green with red antennas. Now he has outlived all my other crabs and is MASSIVE. He has been fine and doesn't bother any one and just cruises around and does his thing. Just today I got 1 small blue legged hermit and as soon as he hit the water the green hermit locked onto him like a heat seeking missile. He tried to pull him out of his shell twice even after I relocated the two. I have the smaller one in my coral-growing tupperware container for the night but thats not a lot of space for long-term. Are these green legged hermits bad because I can't even find any info on them.

In due time I have found all crabs are nasty, aggravating SOB'S and make it my pleasure to give them one chance, then it's time to go. I have none left.....

Don't know about your green legged dude, maybe post a pic. I have about six smaller hermits, combo of blue legged & red legged. They're all good, great little clean up crew. A couple of years ago though I purchased a White Spotted hermit since he looked so cool. Was relatively small when purchased, but didn't take long & this guy got large & destructive. The odd time he'd try to snag one of the little guys out of their shell, but never succeeded. In the end though, he just got too big & I took him back to the LFS where I got him. Before that, he devoured a sand sifting starfish and two pencil urchins. It's entirely possible these critters were doing poorly & he simply finished them off, but he was also just knocking stuff over due to his sheer size. One thing though, when he wasn't doing the bull in china shop routine & eating tank mates, he was one of the best sand sifting critters I've ever had in the tank. Would be a great addition to a sump with a sand bed, but I don't have one of those.

Here's a photo of the dude, with a blue legged hermit hitching a ride on his shell (gives a good perspective of relative size!) & one of the pencil urchins he finished off in the background. And yes, there's a bit of a hair algae issue as well.

https://blufiles.storage.live.com/y1...22a.JPG?psid=1

crabs and shrimp kill eachother