The only "long-fin gobies" I've ever seen sold are actually Vespicula depressifrons. They need brackish water and fresh or frozen meaty foods. I've never known them to take prepared foods. These fish are poisonous so, beware of their dorsal spines. They're also sold as wasp fish due to the intensity of the venom in their stings.
The planets are not in the proper alignment for this darn thing to work correctly. You're simply going to have to post a @^&$%#% pic if you want an ID.