Check out this photo of three different goby species sharing a single burrow. From back to front, the fish are: Stonogobiops yasha, Stonogobiops nematodes, and Amblyeleotris yanoi.
Photo taken in Menjangan, Bali at POS 2 dive site, 23 metres, by my friend Takashi Nagamatsu, who owns underwater camera shop Aquaforum in Japan.
Wish I had been there to see this!