I've now looked more closely and, contrary to my previous statement, the species
C. Leucomelas,
C. Melanistius, and
C. Delphax are not synonyms.
According to my reference by Burgess, I think that they look more like
Leucomelas. I think they're that species for the following reasons;
1) In this book, all photographs exhibiting
Leucomelas have spotting extending through the body into the tail, much like nitro's photos.
2)
Leucomelas appear to have a dark dorsal blotch that extends onto the body, but it doesn't extend nearly as far as that of
Melanistius. Also, between the two lines on
Melanistius there appears to be a 'shiny' spot, which doesn't appear on
Leucomelas (nor in nitro's pictures).
Aside from Burgess' book, I also looked at
FishBase, a very reliable classification website.