tygger November 21, 2007 Share November 21, 2007 So I thought my emerald crab died since I haven't seen in over 6 months... until tonight when only the actinics were on. I don't know what's wrong with him, or if he's been "hibernating," but he's not green anymore. He's pretty much covered in coraline... he's dark purple now... couldn't really see too well and he went back into the rocks when he saw me. Link to comment Share on other sites More sharing options...
DaveS November 21, 2007 Share November 21, 2007 Hmm I wonder if your water chemistry is off. Aside from whether the crab is happy or not, if his shell has coraline algae that indicates he hasn't molted in a quite a while. I've heard that not having enough "something" in the water causes crustaceans to not molt. Link to comment Share on other sites More sharing options...
treesprite November 21, 2007 Share November 21, 2007 is it shrimp that need iodine or else not molt? Maybe that's what it is??? Link to comment Share on other sites More sharing options...
lanman November 21, 2007 Share November 21, 2007 So I thought my emerald crab died since I haven't seen in over 6 months... until tonight when only the actinics were on. I don't know what's wrong with him, or if he's been "hibernating," but he's not green anymore. He's pretty much covered in coraline... he's dark purple now... couldn't really see too well and he went back into the rocks when he saw me. There are RED emerald crabs. Maybe yours was just green young, and turned red over time? Crabs molt, just like shrimp - so do check your chemistry; maybe add a little iodine (not pure iodine - something like Iodion for reefs). Did he seem to be picking at the rock? Seems healthy. I just added two small emerald crabs to my frag tank, and one to my main tank - and I see them wandering around picking at the rocks. bob Link to comment Share on other sites More sharing options...
tygger November 21, 2007 Author Share November 21, 2007 Never knew there were red emerald crabs. When I briefly saw him, he was picking at a rock. As I approached, he retreated behind other rocks. He looks about the same size as when I last saw him. I'll definitely check the water chemistry again, but I have 3 other shrimps in there... 1 cleaner and 2 sexy shrimp that seem to be doing great. The cleaner molts all the time and has grown from <1" to about 3", not sure about the sexy shrimps though. Link to comment Share on other sites More sharing options...
'Ric November 21, 2007 Share November 21, 2007 (edited) Green Mithrax Crabs are commonly called Emerald Crabs, and Red Mithrax crabs can be called Ruby Crabs, or more often just Red Mithrax crabs. I didn't used to add iodine supplement to my system, but when I finally did (Tech-I) my Sally Lightfoot molted the next day. So, I think crabs do need iodine to molt, too. 'Ric Edited November 21, 2007 by 'Ric Link to comment Share on other sites More sharing options...
treesprite November 21, 2007 Share November 21, 2007 Do people typically test for iodine? Link to comment Share on other sites More sharing options...
lanman November 21, 2007 Share November 21, 2007 Do people typically test for iodine? Some do... but when I asked the same question - I was told that the iodine tests are pretty useless. If you have a readable amount of iodine, you have plenty. If you don't have a readable amount of iodine - you probably still have plenty, but MIGHT not. So - I've just been dosing a little bit of iodine, and a little bit of magnesium. I can't give you any scientific results - but since I've been doing that, I seem to have better polyp extension, and my purple digi is finally starting to turn purple. Of course - that might have happened anyhow. bob Link to comment Share on other sites More sharing options...
tygger November 21, 2007 Author Share November 21, 2007 How typical is it for one to change from green to red? Link to comment Share on other sites More sharing options...
lanman November 21, 2007 Share November 21, 2007 How typical is it for one to change from green to red? My red one was red when I bought it. Quite large, also... bob Link to comment Share on other sites More sharing options...
davelin315 November 22, 2007 Share November 22, 2007 It's not unusual for coralline to encrust a living thing as it can grow very quickly and mithrax crabs inhabit the right places for it to grow rapidly - on the edge of the light where nuisance algae will grow. As far as adding iodine, it's a risky proposition to dose it. One safer alternative is to simply add some iodized salt once a month or so. You don't have to add a whole lot, and I don't remember how much exactly, but it's somewhere on RC if you want to do a search and I also believe somewhere on here if you do a search. The proper amount to have present in your system is so little that this is probably one of the safer ways to add it to your system. Link to comment Share on other sites More sharing options...
'Ric November 24, 2007 Share November 24, 2007 Ok- I'm a believer now: Last time I dosed with Tech-I (slow release Iodine supplement) my Sally Lightfoot molted the next day. It's been a while, so I dosed again with Tech-I last night. This morning, my Sally Lightfoot molted again. And, a Scarlet Cleaner Shrimp I bought since last time also molted. Short of actual science, that proves it to me. 'Ric Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now