Purple Crab?

[gogregerson]

So my wife has seen a "purple crab" multiple times in my tank that is similar in shape and size to my Emerald crab. She says it is the same color purple as the mantel on my clam and has fury legs like an emerald crab. Does anyone have any ideas on what this may be? I haven't seen it yet but it doesn't surprise me to have new things pop up.

[hypertech]

Haven't heard of purple, but mithrax crabs come in many colors including grey and red.

I think the key inquiry next time is it its claws are white tipped or pointy and black.

[spectrum]

Are the tips of the claws black?

[gruntmon]

could the emerald have coralline algae growing on it? I know we have tons of snails with coralline on them. could be a possibility

[hypertech]

I've never seen corraline on a crab or a shrimp. I would think the molting would stop any buildup that would occur even if it was possible for it to grow on the shell.

[tico mike]

could the emerald have coralline algae growing on it? I know we have tons of snails with coralline on them. could be a possibility

This is what I was thinking. I have several emeralds and a couple get coralline growing between molts. My coralline growth is pretty rapid. Glen, if you've got elevated calcium, alk and mag (mine are above nsw) it's possible. Unless the crab is completely purple.

[gogregerson]

I have yet to see it but she swears it was completely purple.

[spsick]

My dad and I have seen a few emerald like crabs that were pink or purple. They ended up getting large and oppurtunistic. quite omnivorous, I just use the handle end of my scraper to impale them into the rock, they're tough to catch. sometiumes the glass with food in it trick works.

[gogregerson]

Here is a pic. It seems to be all black with white bands on it's legs. Any ideas now?
http://i242.photobucket.com/albums/ff150/gogregerson/AcroCrab.jpg

[hypertech]

sure looks like a mithrax crab

Maybe hes a variation of a red mithrax?

http://www.aquariumboard.com/gallery/showphoto.php/photo/721/limit/recent

[REEFSTOCK]

cute!

[gogregerson]

Anyone have a positive ID on this guy.

[gruntmon]

Found this mithrax on another site. Also a hitchhiker. (http://www.flickr.com/photos/bclee/139504570/)

[gogregerson]

That looks to be what I have.

[hypertech]

What are you going to do with it? Purple seems to be pretty unique.

[gogregerson]

Keep it for now.