Pistols will usually fourm relationships with most gobies however it is not guarenteed ...You may be able to get one already paired , it is a bit more expensive tho .. Make sure your live rock is firmly planted on the glass or have it mounted on plexi with sand on top as they will burrow under the sand and keep it will stirred . Make sure that you do not have any corals that will be affected negativly if some sand gets tossed on it which is almost a given ... They all in all are a good choice for a nano ...