What's a betta?

First and formost, I'd like to explain what a betta fish is, and why they're unique. You can skip it if it bores you. ;)
Bettas are anabantoids, also sometimes incorrectly labeled anabantids. An anabantoid is a fish with a labyrinth organ, which is a is an organ which lets fish breath surface air, and live in very small spaces. (Wild bettas live/lived in shallow bodies of water, like flooded rice paddies.) This organ makes them ideal pets to keep in small bowls and cups.
Bettas are also famous for their long flowing fins. These fins were originally quite small, but genetical engineering has changed that. There are still bettas with small fins though. There are several kinds of bettas. There are "plakats" and "halfmoon plakats", the shortfinned variety. (I prefer this kind.)
Secondly, there are "halfmoons", a type with erect tail fins that span 180 degrees, thus the name "halfmoon". There are also "crowntail" bettas, with fins that look like the rim of Batman's cape, only much more so.
Thirdly, there are "veiltail bettas", which is the kind most people find in petshops. Veiltail bettas have long drooping fins. Fourthly, there are bettas known as "deltas" or "super-deltas". I don't see much difference between them and a halfmoon. (Any knowledge on this? Please comment.)There are also some miscellaneous types.
Bettas are also well known for their fighting urge. For some reason bettas are apathetic to other fish, but like to beat up their own kind. Males will try to kill other males, and behave brutally to females, unless they are in breeding condition. Even then, they will be pretty mean.
As anyone who has kept a betta can tell you, male bettas love to flare their gill covers. (I'll post a picture of this soon.) They will flare at other bettas, bright colors, foreign objects, and just about anything. Females may do this, but rarely.
As you can see, the betta is a very interesting fish, with a lot of personality. Also, you may have noticed I've left some stuff out, like bubble nests. I'll tell more about this stuff in posts to come. :)