Randall’s Shrimp Goby

I am fascinated by shrimp gobies in general, and I particularly enjoy Randall’s Shrimp goby, Amblyeleotris randalli. It’s one of these clever little fishes which lives in a symbiosis with  burrow-digging shrimp. It stands out from other shrimp gobies by it’s enlarged dorsal fin, and by it’s preferred habitat.

The goby very often moves its dorsal fin in a slow, rhythmical manner, especially when it does not feel threatened, and perches in front of its burrow. This can be observed quite well in this video:

A lesson Randall’s shrimp goby taught me is how finely grained different habitats are in a coral reef. The first time I saw this fish was in one of the outer islands of Okinawa, the Keramas, where the fish was living relatively deep (> 20 meters), under an overhang. This seems to be the preferred habitat of this fish, I mostly see it under overhangs, and rarely shallower than 20 meters. Other shrimp gobies almost exclusively occur in shallow sea grass areas, yet other species only in the sand at around 10 meters. Moving a few meters deeper or from an area with seagrass and sand to a sand only area will immediately change the fish fauna. Randall’s shrimp goby is the shrimp goby which specializes on deep overhangs, not a very common habitat, but one which for some reason (fewer predators? specialized food sources?) fits the needs of this fish.

On Apo island, at the “bubbles” dive site, there is an overhang at about 26 meters which usually has a few of these gorgeous little fish. The overhang often also has some mid-sized groupers on its ceiling, I have to wonder of these are fancying the gobies as lunch. As always, but especially when inspecting an overhang with fragile organisms on its walls, please be careful when diving and practice good buoyancy.