Blacktail Chromis Pycnochromis (prev. Chromis) nigrura

The Blacktail Chromis is native to reefs of the Indian and western Pacific Oceans. It swims in groups and grows to 5.5cm long.

It is a greyish brown chromis with yellow cheeks/flanks and lines of blue spots along the flanks. The anal fin is dark blue. There is a dark line along the top of the dorsal fin. The tail, from which it takes its name, is yellow, usually with a thick black border along top and bottom.

It is very similar in looks and habits to both Vanderbilt's Chromis, Pycnochromis (prev. Chromis) vanderbilti, which does not have the upper black border on the tail (just the lower border) but has a yellow upper lobe, and the Lined Chromis, P. lineata, which has no black borders to either tail lobe.