What are your thoughts on these guys? Reef Safe? I have 2 or 3 emerald crabs I've had for about a year, and they are getting mighty big. Anyone had one catch a fish or attack? I'm thinking maybe I should consider putting them in the sump.
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What are your thoughts on these guys? Reef Safe? I have 2 or 3 emerald crabs I've had for about a year, and they are getting mighty big. Anyone had one catch a fish or attack? I'm thinking maybe I should consider putting them in the sump.
Ever see them eat coral of any kind?
I would have them again - but only very small and I would pull them out after they cleaned up the tank and before they got large.
Well, I've taken heat for saying this before, so here goes. Personally, I would never ever trust an Emerald Crab or a Sally Lightfoot in a tank full of zoanthids and Playthoas. Both are continuous and voracious eaters. I have seen and caught both doing just that, munching on my polyps. I firmly believe that Emeralds are highly unpredictable. They may walk by your poylps for years and never touch them, but one day, I can assure you they will. Emeralds are herbivores until their shell reaches the diameter of quarter. Once they mature beyond this size, it's like russian roulette and they will become omnivores from my personal observation and anectdotal reports. There are countless threads on another sight of them eating/consuming zoanthids. I will go a step further and say that no flat crab, as I call them, is considered reef safe around zoanthid and should never be trusted. I have caught 6 adult crabs, not emeralds, in my tank and I have devisied a way to remove each of them. If I had a small system with a few inexpensive zoas, I would leave them.
A. Calfo has even stated in his book, "As a rule, most crabs should be considered unpredictable to dangerous, as few are truly herbivores. Even the "safe" crabs like the algae grazing Mithrax species and seeral of the sand stirring hermits have occasionally been observed eating or attacking other reef denizens. The truth of the matter is that most crabs are truly omnivores and opportunistically predatory."
No offense, but whenever a see a speck of bubble algae, I rolled it off the rock. But I will never ever trust an emerald crab in my tank that's loaded with zoanthids and playthoas. Just my 2 pennies.
Mucho Reef
My experiance is similar to others. When my emeralds were small they did a great job but as they grew they would knock frags over and I witnessed them ripping flesh from acans trying to get to the mysis shrimp the acan was trying to eat. But again this only started when they were over quarter size. I have also seen sally lightfoots going after small fish - not in my tank but others locally. I hate it because I like the crabs for all the good - but I don't want the hassle of possibly tearing my rock work apart to catch them either.