Stay away from them. Don't even bother unless you can provide a 2000+ gallon pond. They get HUGE (4+ feet in the right conditions!) and really aren't suited for home aquariums. They are brackish and sometimes fully salt water fish anyway. Sorry for the harsh response, just trying to save a disaster
__________________
My tanks (so far

)
5.5 gallon Planted Dwarf Puffer tank (2 Dwarf Puffers and a lot of RCS!)
16 Gallon Planted
(GBR pair, 3 amano shrimp and a whole bunch of snails!)