What do you want to know? They're pretty easy fish provided you positively ID the species on sale beforehand. There are three common species in the trade, only two of which need brackish water and the remaining species (T. microlepis) prefers freshwater conditions. They are predatory but not normally aggressive except to their own kind. Often work best either singly or in fairly large (6+) groups; in twos and threes the biggest one tends to become a bully.
There's lots more in my brackish FAQ, and both my book and the Aqualog book on Brackish-Water Fishes have lots of information on these fish.
Cheers, Neale