The pic you posted is Stiphodon atropurpureus. They are essentially unavailable in the US. Lots of people claiming to have them, and sending out s. semoni or something similar instead. They have really specific dietary and husbandry needs, so definitely not a fish you can just chuck in a community tank. Rhinogobius, schismatogobius, and hypseleotris are better bets for mixed company because they will generally gladly eat prepared/frozen food, whereas the stiphodon can be immensely pickier depending on the particular fish. None of the commercially available fw gobies sift sand as far as I know, but a good lot of them spend a lot of time digging, which essentially serves the same purpose.
Can you recommend any places that sell freshwater gobies?
Im just looking for the most colorful i can get. a good mix. Just looking for the smaller sizes say 3" max.