I have gone through 5 emerald crabs and currently only have 1 small ruby. My Dottyback thinks they taste really good. The only reason the Ruby is probably still around is because she is small enough to hide.How many emerald crabs do you keep in there? I love them for algae control except when they get too big. That is when I see them going after fish with more determination.
My largest I ever had was in this tank, easily 2in wide body. I never considered sexing the crabs. Seems like such an easy thing to do with us boys that grew up on the Gulf.I am not sure of the measurement, but it was one of the largest I have seen in aquaria. It would hang on the rock and claw after the fish as they passed by. I fed the tank enough I am sure. I guess they get a desire for fresh meat when they get older. I heard from Joey at Aquarium Central that one sex is more aggressive than the other. Is it the males? I have a hard time telling them apart.