thinking about doing a brackish tank - suggestions?

Mollusks and crustaceans are loved by puffers, but, as you guessed, not as tankmates, but rather entrees. I wouldn't chance a mixing of the two except when your puffer needs food (and snails/crabs/crayfish will help keep puffer teeth trimmed).
 
BB, I have a 50gal BW-SW (1.019-21) w/2 (5") GSPs (Cricket & Bozo), a (3") Ceylon ((Cammie) & 3 (brown?) damsals.
 
No, Bumblebees are brackish and 1.019-1.021 is saltwater. Plus the Damsels would kill the Gobies. Damsels are inch for inch the nastiest fish available. What they lack in size they make up for in temperment. I have two Blue Devils and they give my 4 Bar Gobies a hard time. There are plenty of other saltwater goby options like Shrimp Gobies, Cleaners, Dart fish, and Firefish. If you want to do a saltwater tank a very easy very cheap set up would be a tank with some live rock, a Firefish, and a TR Percula or Ocellaris Clown. Clowns are not near as aggressive as their close cousins the Damsels. Both fish will be under or around 20 bucks each and will bring enjoyment and color to your tank. Hope this helps and good luck.
 
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