Expert: Susan Fields - 7/5/2009

Question
I found a crab and I think it is a shore crab. is was in a tide pool, someone handed it to me and I thought it would be a nice addition to my aquarium. but I can not find any information on how to care for it. I know what it eats, but how about what type of water? can it be adjusted to freshwater? it looks like he is breathing air not water therefore I need to make sure that he can get to it? I don't know and I am disappointed that I could not find more information. I could use any information that you have. Thanks in advance! God Bless! -Elizabeth  <><

Answer
Hello Elizabeth!

Very interesting creature! I wish I could see a photo of it but that's ok!

Without knowing the species it is difficult to have much to advise about on the little crab. However, obviously since he was found in a tide pool, he is a saltwater loving species that may stay mostly underwater all the time or more likely come out occasionally like many crab species to forage around. I believe as long as their gills stay moist they can be out of the water. And I do know some crabs can become quite sickly if they do not have any access to crawl out and get some air.

The ideal setup would be to keep him in a saltwater environment with sand and part-land/part-water somewhat like a "beach" or try floating some driftwood/plants that reach to the surface and form a sort of island (provided the water level is low enough beneath the hood) in order for him to crawl out on.

Being wild-caught -- the crab is likely to be quite sensitive to changes unless you are lucky and have an adaptable and hardy species. Otherwise, to my best knowledge he may eventually fall ill due to being kept in freshwater and would thrive better if he had his own little tank with some synthetic sea salt mix intended for marine aquariums to create a saltwater environment. (aquarium salt doesn't contain the same minerals and additives to make the water truly marine)

I wish I knew more but best of luck with the little guy!
Karen~