Join Date: Jun 2010
Location: Jakarta, Indonesia
Yes, they don't. But shows must reach 180* spread. Anything below that is faulted.
HM is basically a half circle formed by all 3 fins. The caudal must reach 180* spread. For shows, the dorsal must at least be upright. Stair . . . Not sure what to call it . . .. where front dorsal rays are short and gets higher at the rear ray . . . .anyway, this is faulted. Anal front ray should lean forward while the rear ray should either slightly slant backwards or straight down. All 3 fins should meet/overlap.
Delta are those caudals that do not reach 180* spread. The sides should be straight. Super deltas are close to 180* but don't quite make it.
Those with curved sides (like your guy) are also considered delta (though IMO they should be called something else). In terms of breeding these might be the worse in the sense that they are very difficult to fix (create fry that has a perfect "D" shape caudal). Even if they do produce HM fry, the caudal edges will remain rounded.
I don't mean to discourage you, but you asked for a show perspective overview.