I looked into this a while back and found this on the web.
There are a few identification checks to make between H.nemerus and H.wyckioides. H.nemerus has a smaller adipose fin and a identifying black mark on this fin. It also possess a filament extension to the top caudal lobe and there are a few specimens that do not even have the pinkish/orange colour to the caudal but have the same colouration as the body.
Also H.nemerus does not sport a truly red tail, more of a pinkish/orange variety, when older. But from the pic and the nipping of his fins i cant tell 100% at the moment