you can fish yourself one of the rays from the St Johns river system... they are permanent FW.....
I really like Micronema apogon or Beledontichthys dinema... perhaps 3-5 of one those species. another favorite of mine (not rare but fun fish) are the sleeper gobies... marble or otherwise. Get about 1-2 ft long. Not rare but not many folks keep them. ANother GREAT FISH as far as interesting and uncommon is Mormyrus kannume... will hit 2FT or more, but biggest you can buy usually is about 11-12 " and grow slow. Fascinating fish.
ALso, common, but you don't see many fullgrown ones: Mbu puffer
Dunno if you like bichers, but P. endlicheri is a nice BIG bicher, a little less common than some others.
just some ideas (not sure what is legal or not in Florida).
Tigs are boring... get yourseld a big ol Irwinni or P. niger or P granulosas instead.!!