Q: How do you know how old your betta is??

Question submitted by Laura, Richmond - British Columbia
A: If bettas were horses, we'd look at their teeth. If bettas were birds, we'd look at the skin texture on their legs. If bettas were people, we'd ask them, listen to their answer, deduct 5 to 10 years and have a good idea of their age. LOL

But bettas are not so simple. If you were to bring me a betta today and ask me to estimate its age, how would I go about it?

I would look for the following clues:

bulletsize: If a betta is very small, it usually is very young. The larger a betta, the more likely it is to be older. However, some bettas grows to huge size prematurely, and some others stay tiny even when older (dwarfs). So as you see, it is not a sure thing.
bulletfin length: If the fins are very long, the betta is likely to be fully mature (1 year) or older. A betta with shorter fins, or one with hardly any fins is a young betta. Young bettas can look just like females. If you are trying to estimate the age of a female, finnage length will not be of any help. Also some males grow fins much faster than others, and I have seen males 1 year old that looked almost like females.
bulletattitude: A young betta is more active, and if healthy will swim a lot and with great energy. The older a betta gets the more lazy it gets LOL. However, a young betta that is unhealthy can be very inactive, so there again, you can't be sure.
bulletQuality of finnage. An older betta's fin may look less flowing, show some sign of wear and tear. However a young betta with fin disease will also show such signs.

In closing, it is very hard to estimate with any kind of certainty, the age of the bettas from unknown provenance. That is why once again I must stress that if you are serious at all about your hobby, you purchase your stock from an established, experienced breeder only. Such breeder will be able to tell you how old the betta is, not because he/she can guesstimates, but because he/she KNOWS, since he/she keeps track of spawn's birth month and knows all their spawns/bettas intimately.

Hugh, wise buffalo has, once again , spoken ;).