Colubraria nitidula is the most common species of the family found in the Marshalls. During the day it is most often seen under rocks, usually in groups of three to about ten specimens. At night it is an active parasite of sleeping fish, usually parrotfish. On one occasion, we observed seven specimens with their anterior ends poking out of the sandy floor of a small seaward reef ledge and their elongate feeding probosces stretching upward to suck the blood of a nocturnal Priacanthus sp. spending its day sleeping in the reef.
Below, several shells are under a sleeping scarid at night.
The probosces of at least a couple of the shells can be seen extending upward into the parrotfish. They appear to be going under plate covering the gills.
The next two shots show a specimen on the mucus bag surrounding the sleeping parrot. The Colubraria's proboscis is stretched through the mucus bag and into the parrot's mouth.
Although the shot below has poor contrast, it shows that Colubraria appear to go for parrotfish fins as well.
This one is also on the parrot's mucus bag. The proboscis is barely visible below the anterior end of the shell, extending into the parrot's mouth.
These appeared to be on an egg mass.
Created 24 October 2010
Updated 5 March 2020