I wouldn't recommend it. Most of the freshwater gobies are better kept in brackish setups. It's not impossible but quite difficult to keep them in a freshwater setup without some kind of disease cropping up. I'd go with dwarf puffers myself.
They are said to be about as active as stones, so keep that in mind. Most bettas do not go on hunger strikes as yours did, I have a female betta who is probably my favourite fish right now; inquisitive and very pretty