I'm thinking about making my 35l desktop tank into a brackish one, rather than a shrimp tank as I'd planned originally. I've never done brackish before so I need a bit of advice. It's a pretty tiny tank, so the range of fish I could keep is probably quite small.

I want to move my whitecheek goby from my freshwater tank into it (my otherwise excellent LFS insisted it would be fine, but I've been hearing otherwise) and maybe get some pygmy puffers, if they'd be peaceful enough. I'd also like to put various little gobies in, like dwarf dragons and maybe peacocks- do they do well in brackish? I've also heard celebes rainbows do better in brackish. What species would do well in a brackish tank of this size?

Thanks!