The Rainford’s goby, as well as the lesser known Hector’s goby, are pound for pound some of the most colorful, interesting and perfect little fish for the reef aquarium and last year we got a new species to induct into their club. Koumansetta hoesei is just the third species of these little missile shaped gobies and although it’s been a few years, we actually used to see the ‘Red Sea Hector’s Goby’ in the reef aquarium hobby with great regularity.
Once part of the larger Amblygobius genus, Rainford’s, Hector’s & Hoese’s gobies are physically much smaller, thinner, more streamlined than their thick dragon goby counterparts. Interestingly, while their fins are mostly clear, the members of Koumansetta are more deliberately patterned and colored than the mostly grayish Amblygobius .
The newly described Koumansetta hoesei is known only from the Red Sea and looks very similar to the Hector’s goby at first glance, and to be fair on second glance as well. The biggest visual difference between K. hectori & K. hoesei is mostly in the definition of the lines; the classic Hector’s goby is darker overall being a deep chocolatey brown with distinct unbranched thin yellow lines.
By comparison Koumansetta hoesei is slightly lighter in coloration, especially towards the ventral area, and the yellow lines are more branched and split up into smaller lines particularly around the head and face. At first glance the new Koumansetta hoesei has a passing resemblance to Rainford X Hector’s Hybrid which can be found in Indonesia but this is pretty superficial and easy to rectify if you know where the fish are coming from.