Join Date: Jun 2010
Location: Jakarta, Indonesia
Older Bettas sometimes are reluctant to flare, especially if they were never flared regularly or was never threatened by other Bettas. But don't be fooled. That doesn't necessarily mean they won't fight when threatened. And that doesn't mean they will be mellow when breeding.
If he is too passive, it may be a problem. The female may attack him (better because he will fight it out) or in the least, take sucker bites which will eventually stress him (not good). So keep an eye on him if you ever decide to breed him - weather passive or aggressive.
The main problem might be getting him want to breed. Usually you'd need to manipulate him more than aggressive Bettas. One method is placing him in a smaller tank next to a rival. Then tap his caudal with a long thin stick. This will imitate or make him feel he is being attacked. If he responds, keep doing it until he fights back. Otherwise, try other methods as this may stress him.
Another method is letting him see or let him be with a flirting female. If he responds, whether to fight or breed, he can be bred, after more manipulating of course.
Don't wait for bubble nests, because he will unlikely make one until he is actually breeding. Look for body language signs - flirt swimming.
*** raise temp to 28°C.