When it comes to bettas, there are many different tail forms the male betta splendens can ultimately have.
The most common ones are the crowntails, the veiltails, deltas, super deltas, plakat tail, and the halfmoon.
Not all of these tail types are fully recognized by international breeders, but thanks to the International Betta Congress, there are some hard-set rules that have been agreed upon to help determine the perfect betta form.
In terms of the halfmoon betta tail, there are many traits that should be considered when trying to breed the perfect fish.
Since body form is discussed elsewhere, the focus here is on the characteristics of the three main fins.
These three fins include are the dorsal fin at the top, the anal fin on the bottom, and the caudal fin - the betta's tail.
There are a few traits that make up a quality dorsal fin.
The first is that it is nice and broad along the length of the fish.
The front edge of this fin should project forward and should have a nice curve that lets it meet the caudal in a smooth arc that matches the curve of the tail.
Ray branching is allowed in the dorsal.
For the ideal anal fin, it should have two sides that sweep out from the body giving the outer edge of the fin a wider arc than the edge that meets the body.
Another important trait is that the outer edge follows a similar arc as the body does.
The caudal fin is perhaps the most important individual part of a halfmoon betta overall.
The ideal shape is very similar to that of a capital letter D.
The outer aspect should form a perfect half circle.
The two edges should be perfectly vertical and meet the arc in a nice crisp point.
Outward pointing rays can help produce this vital characteristic.
Finally, the overall shape of the betta's fins should be complementary and balance each other.
The three main fins should come close to forming a circle which is why smooth transitions are helpful between fins.