I got a couple of hitchhikers with my Macroalgae six months ago. The first crab was about 1/4" if you measured the spread of leg tips. I have been able to tenatively ID it as a Red Ruby Mithrax, and it has grown more than ten times that size since arriving being now just over 4". THe second crab was tiny about 1/8" and white when it arrived, and has maybe doubled in size about 1/4" max tip to tip now. I tried to get a picture, but camera was either out of focus or you couldn't make out the crab against the rock. I will continue to try to take a picture, but I only see the crab out every couple of weeks, so it may be sometime before I get another chance. Does this sound like any crab that people have experience with or is it just an odd phenomenon? If I were to describe it I would say it looks like a thai micro crab only a little smaller and thriving in saltwater.
Both crabs estimated based on leg tip span measurement.
Both crabs estimated based on leg tip span measurement.