The hole this fish lives in is not a hole. It is a system: a main shaft, side chambers, more than one entrance, and a lining of coral fragments and shell that the shrimp packs into the walls to stop them falling in.
And it is always falling in. A burrow in loose sand collapses continuously, which is why the shrimp is out at the entrance every few minutes pushing another load of spoil into the open, and why the excavation never actually finishes. Over weeks the whole structure migrates across the sand as one end is abandoned and the other extended.
At dusk both animals go in and the entrance is sealed from the inside, and the sand flat that was full of small barred fish at four in the afternoon looks empty an hour later.
The goby's part of the deal costs it the reef. It has a burrow and a bodyguard, and in exchange it spends its entire adult life within a body length or two of one hole in the sand.
The genus. Amblyeleotris Bleeker 1874 - amblýs (blunt). ETYFish
- whitish body with five wide brown bars and scattered brown spots
- two thin dark bars running at an angle across the snout and cheek
- yellow anal fin with a blue margin
- never more than a body length or two from the burrow mouth
- up to 11 cm
