Bumble bee gobies are a brackish species and will suffer if kept in freshwater,they are also notorious fin nippers and should only be kept with species with no long fins and that are able to look after themselves,good tankmates are small puffer fish .
If you are interested in small freshwater gobies then look up peacock gobies TATEURNDINA OCELLICCAUDA,possibly the most peaceful of all gobies they are suitable for small tanks and are easy to breed.