Emerald crab reproduction questions

"Umm fish?"

Premium Member
My lovely bride spied a baby emerald crab hiding in the live rock this evening. It's about the size of a dime. I have a very large emerald (male?) and three crabs that haven't changed size much since I got them.

My questions: What are the chances the new one is one of their babies? Do these crabs have a planktonic stage? If so, how long?


i doubt one is a baby....these guys have very intresting social structure though. From what I have seen the larger one grows to be the leader. He will continue to grow while the other stay small. I one time removed the larger of my crabs and one of the others remaing started growing again. He grew to be the new larger crab. While the others stayed small. It was very intresting how they can control there own growth (at least that is what it seemed like to me).
He's enormous. I mean, "scare the kids" big. :)

None of the crabs I put in was less than a quarter in size. brokecoloreefer--If you're out there somewhere, did you have any tiny crabs in your tank? That's the only other explanation that I can think of....
Which one? I haven't gotten the best look at the little one yet. It's understandably a little shy. It was hiding in a cave just barely bigger than itself right in the front of the tank, reaching out and scraping what it can off all the rocks around the opening for about half an hour last night. It's pinchers come down to the same dull ends (not points) as the others and it has the same hairy, brown back legs. It's hard to explain the pincher ends, but if you know blacksmithing they look like the anvil ends on a power hammer that have mushroomed a bit.

The large one is just the same as the midget. He's forest green, much less shy (obviously), and the worse thing I've ever seen him do is to eat some corraline. His body is more on the order of a fifty-cent piece or a little larger, but his extended arm-span is probably 5-6". He got in a defensive posture and ran away from a blue-green chromis the other day, so I'm not so worried for the fish. :)

I tried to proof this, but I'm sorry for any typos. My arm's in a sling today (bicep tendon) and I'm trying to type one-handed.
I have an Emerald Crab and that was the only crab I had in my tank so I thought. 9 months later I spot not one other crab but two! One looks somewhat like an Emerald Crab but thinner and the other is much thicker and compact looking. I assume they had hitchhicked in on LR. They ONLY come out at night. Even though I look in the tank all the time at night using a colored lense flashlight it still took me all that time to see them. Being that I'm using a colored lens I can't really tell what color they are and they are very shy. Just my experience.
I had a few emeralds in my tank. I never put any other crabs or rock in then one day about a year later I find a small crab that looks like a emerald but is black/purple and a bit thinner than emeralds. It also had white tips like the emeralds I had. I have no clue how I got them but can tell you I found them after some trades I did with Ryan (still don't know if they came from him). I never noticed them doing any harm but just to be safe I took them out when I did the tank move.
Trex420-- Thanks. It was def. active with lights on. But, it was in a shadowed area.

Joe--Gotcha. I'll keep an eye out. If it doesn't get any larger, I don't think it'll do much harm. If I see it again, I'll certainly try to get some pics. Just didn't want to try with the gimp arm.