You will love your pistol/goby pair. I have a Tiger Pistol named Bulldozer and a Blue Spotted Watchman Goby named Mugs. They paired up immediately and are lots of fun to watch. Your kids will have lots of fun watching them. Be prepared, though, for that pistol to move lots of sand. Mine also grabs snails and hermits and drags them in his hole and they crawl out and he catches them again. This can go on for hours.