ID this, and advice please

he came from the 'Big Blue'. My younger brother brought him to me. is it safe to have him in there??

 

Looks like a large zebra stripped hermit crab to me. You will probably need some empty shells about the same size or slightly larger to keep him happy. Reef safe yes but he may give your snails or other hermits a run for their money, if they can get away.

 

Also known as thin stripe hermits, they can get pretty large, my LFS has one thats about 6". I would watch him carefully with other inverts as Corailline said.

 

I had one of these for about 3 months and my mean hermits killed it. I literally saw the electric red hermit repeatedly and relentlessly with his claws, punch the thin striped hermit and pull him out of his shell to take it over. I got a bigger shell for him 2 hours later but it was too late.

 

Very nice hermit reminds me of the land ones.

 

so shrimp aren't safe to have around him?

 

If it finds a molting shrimp or one just molted it will probably eat it. A good note though, a friend had a large one like that and it ate GHA like no tomorrow.

 

I had one for 4 years that I got in an "empty" shell at the LFS. He got the size of my fist. Never hurt anything in the 2 tanks I had him in, he was afraid of the blue damsel he was originally in with, tho he could have easily eaten it in about one bite. He was a huge klutz, I'd hear him fall off the rock & hit the glass at night LOL. I ended up having to get a bag of big shells from a craft store for him.

This pic, the shell on top is the shell he came in and the shell he's in came from a beach in Scotland. He was 2 years old in this pic and got a bit bigger by 4 years. I never had a hair algae problem after getting him, and the 10 gallon he was originally in had every bad thing in it when I put him in.

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wow... that's big :/ idk if he'll be able to fit in my aquarium if he gets that big....