Delta or Halfmoon

[kermadum]

I bought a couple of what I was told were Deltas at Aquapets last week, but this black one, seems to be spreading into a halfmoon, is that common?

Starting his bubble nest

Sittin pretty

I paired him up with one of my copper black halfmoon females and he's been quite active getting a nest ready and his flaring seems to be stretching further and further.

This peach coloured one is clearly delta (he's in a round tank for the moment, and getting a good photo is difficult), so there's no question on him, but thought I'd stick this photo up anyway, I love his colouring.

Not looking too excited, but hanging around

[shadoh]

Some beautiful fish you have there! To me he looks more like a super delta. The "corner" edges of his caudal look too rounded

[paul]

Adam, it is possible for a beta's form to change with conditioning - or indeed lack of conditioning. The idea of carding and exercising these guys is so that they maintain their form. When a fish has been left without exercise for a prolonged period, the fins will not stretch up to the same extent as when the fish gets regular exercise. If the black male you have pictured manages to get his caudal to 180degree spread with increasing his flaring and exercises, then you can call him a halfmoon. Although as Shadoh has pointed out, ideally you would have sharp corners to the "D" shape, he would still be considered a HM.

[kermadum]

Great. Thanks for the tips folks. His spread is so very close to 180 degrees when he is at full flare (much closer than when I bought him), so he may spread to that halfmoon shape, but I doubt that the corners of his fins will get sharper. I don't mind, he won't be getting pressured by me to be anything other than himself, but curiosity about what other people think got the better of me. He's a hilarious little fella with a tonne of personality. I think I have a bit of a fish-crush.

[Neffy]

Ohh i hope with exercise he does reach it, he is very close and a pretty fish!