7) Shotsilk Goby

P.zebra

Despite its name, the Shotsilk Goby Ptereleotris zebra is not a true goby at all, but rather a dartfish in the family Microdesmidae. There are around 20 species in all in the genus, with numerous other genera, mostly in the tropical Pacific and Indian oceans. They are all elongated fish with often eel-like bodies, and most live in burrows or other concealed locations. Some enter brackish water, and at least one, Pterocerdale from Queensland, Australia, appears to be a freshwater species. The English name refers to the iridescent fabric called shot silk, which refers to their shimmering colours. Several other species of dartfish are also seen in the aquarium trade, but at present all are wild caught – there is no commercial propagation of these fish.

Shotsilk gobies are diurnal, hovering in the water column in large groups to feed on passing zooplankton, but they are rather nervous fish and will quickly dart back into their holes if they feel threatened. They are small fish, reaching around 12cm as adults, and prefer shallow water. They have a large range, extending from the Red Sea across to the Great Barrier reef and north to the Ryukyu islands.

Nemateleotris magnifica

There is very little information on the reproduction of Ptereleotris. Some dartfish are found in pairs, others seem to form harems. There is no information as to whether, as with many marine fish, they can change sex in response to age or dominance hierarchy. It appears a pair once formed may defend a nest site and the eggs are laid in a single mass that is cared for by one of the parents, but whether this is the male or female is uncertain as they are identical. I have not been able to locate any information on raising the young, but they would be pelagic and extremely small, so any captive reproduction would probably require extremely small plankton such as nauplii of copepods to raise them. Many true gobies have similar larvae, and a few are now being commercially raised.

Given their wide distribution Ptereleotris spp are not considered threatened at present. The only commercial fishing would be for the aquarium trade which would have limited effect. Loss of reef habitat as a result of shrimp farming and agricultural pollution would be a more serious threat.

Images from Wikipedia