Behavior
This species shares a burrow with its shrimp partner. The goby has much better eyesight than the shrimp, and, as such, acts as the watchman for both of them, keeping an eye out for danger. The shrimp spends the day digging a burrow in the sand in which both live. Burrows usually measure up to one inch in diameter, and can reach up to four feet in length. The two animals maintain continuous contact, with the shrimp placing one of its antennae permanently on the goby's tail. When danger threatens, the goby will make continuous flicks of its tail, warning the shrimp there is a predator nearby, and the shrimp will remain safely in the burrow. If the danger reaches a certain level, the goby will dart into the burrow after the shrimp.At night, the goby will go into the burrow, and the shrimp will collapse the entrance to close it off. The burrow is exited the next day by the goby blasting its way out and collapsing the burrow. The shrimp then spends the next day laboriously rebuilding the entrance to the burrow. Both animals have also been known to share food with each other.
When the goby catches food, it will often give a portion of it to the pistol shrimp, through a somewhat similar process of a mother bird regurgitating food to her chicks. This way, the shrimp and the goby are kept well fed. Sometimes, if the shrimp is not kept well fed, it will resort to killing the goby.
In the wild, most burrows are shared by male and female goby pairs, with their respective shrimp partners, and the female goby will use this burrow as a nesting site to lay her eggs.
The obvious benefits to both organisms of this symbiotic relationship make the interaction a form of mutualism. of this. The other fish is a dartfish . These fish are often found as unwelcome but ignored guests sharing the burrow with goby and shrimp.This fish is very docile and poses almost no threat to any other stock inhabiting a typical marine aquarium. This passiveness makes it a perfect tankmate for delicate species like sea horses or pipefish. In fact, it is in reality quite shy, and when first introduced into an aquarium, may take up to several weeks before it is bold enough to leave its hiding place, or bolt hole. While this fish can display aggression towards other tank inhabitants by opening its mouth and "yawning" at them, this is mostly show, and the goby will quickly turn tail and hide if confronted.
The goby will spend most of its time hovering about two inches above its bolt hole, searching for scraps of food in the water column. If scared or startled, it will slowly retreat towards its hole. If the danger does not go away, it will dart inside at lightning speed.
Mated pairs of this fish are very rare and difficult to attain. Individual males may fight if placed in a tank smaller than about 50 gallons .
Habitat
This goby inhabits sandy or sand-rubble bottoms adjacent to reefs at depths of from 15 to 25 metres . It is one of several species that form commensal relationships with Randall's pistol shrimp .For successful aquarium culture, this fish needs good sand/coral rubble cover for burrow-building and much rock cover; a reef environment is suitable. The recommended minimum tank size is 10 gallons , however these fish mainly hide out in burrows all day, and are not active swimmers, making them candidates for smaller "pico" aquariums. The water specific gravity should be 1.020 - 1.025, with a pH of 8.1 - 8.4; water temperature at 72 - 78 °F / 22 - 25 °C is ideal, however water temperature up to 80 °F will not harm the fish.References:
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