Hi there --
Thanks for the kind words.
There are a couple of brackish water herptiles, though how widely traded they are is not known to me. One is the diamondback terrapin, a brackish to marine 'turtle' from the US. It is quite large though, and would certainly eat a mudskipper or any other fish. The other brackish water beast I know of is the crab-eating frog, Rana cancrivora. It is (if I recall correctly) the only amphibian capable of living in salt water. Again, while I have heard of them being kept in captivity, I don't know enough about the reptile and amphibian hobby to know where to obtain them or how easy they are to find.
Provided there was a pool of fresh water for drinking, I'd imagine tree frogs, lizards, and snakes would all be options. Certainly, there are lots of these animals in mangrove forests. A better bet, though, would be crustaceans. Virtually all of the amphibious crustaceans sold to aquarists are really brackish water beasts; the one exception I can think of is the rainbow crab, Cardiosoma armatum. But things like fiddlers, hermit, and red-claw crabs would all thrive (and look really cool) in a mangrove forest 'tank'. You could also see if you can obtain a coconut crab, Birgus latro. These are giant shell-less hermit crabs, and very very impressive.
The only problem with paludariums, which is what you're making, is fungus. Enclosed, damp, warm spaces tend to get fungus quite badly unless you make sure ventilation is spot-on. I would imagine there are people who know more about this on reptile forums.
Cheers,
Neale
and he is quite smart on this type of stuff)
