Half-Black Angelfish
Pterophyllum scalare
About this strain
Half-Blacks have a sharp, almost painterly division: the front half of the body is silver or lightly colored, while the rear half transitions to deep, solid black. When the dividing line is crisp and the black is fully saturated, it's one of the most dramatic color patterns in freshwater fishkeeping. Quality varies enormously — the transition should be distinct, not a muddy gradient. The black coloration is caused by a separate genetic mechanism from the Dark gene. Fin development and body depth should still meet standard conformation expectations; don't let striking color distract from evaluating overall fish quality.
Origin
Developed by angelfish breeders in the United States during the 1960s–70s. Specific originator lines are not well attributed in hobby literature.