Bio- what? What's in the centre of it and what does it claim to do? I've never heard of it, but that doesn't mean it's crap.. I'm just trying to think of what the hell it might be.
Usually stuff that you leave in your tank for ages is either supposed to absorb something (ie activated carbon and zeolite - both unnecessary) or release something (ie pH stabilisers which are a total pain in the butt).
So yeah, I tend to be a bit pessimistic about stuff like that too because it's often a sales pitch, but for all I know it could be really useful. Need a bit more info though, I've never heard of it.
An elaboration on the bubblenest thing: in the wild, a male betta will claim a territory. If any other males appear, he will display to them (flaring). This is a signal that the territory is claimed, a display of aggression (don't move another inch, buddy) and also allows the other male to decide whether to challenge or not. A superior male may drive off the original owner of the territory; an inferior or well matched male will usually move on and find territory elsewhere, and there will never be a fight. (This is one of the reasons everybody on this forum hates betta fighting: putting two males in the same tank does not give either of them an option to leave and forces a fight, which is a very unnatural condition.)
Once he's claimed a patch of territory and in between defending it, most males will build a bubblenest. This is because the females tend to roam around the body of water (in which there may be a LOT of males) and fill with eggs naturally. Males will display to them as they pass, but if they are not interested in mating, they will ignore his display and leave. (This is why a male will attack a female that is not ready to mate - he is confused because she neither leaves nor responds to his courtship.) If they ARE interested in mating - well, he'd better be ready, or she'll go for the male in the neighbouring territory. So that's why most males will build and maintain a nest in the wild. A lot of captive bred bettas still do it, but some of them don't. The amount of time and inbreeding that goes into something like the cultivated strains of betta tends to dilute and modify natural behavior to some extent. There are some species of betta that will mate repeatedly and may have eggs and fry of various stages and different mothers all hanging around the one nest. I don't THINK Betta splendens does this, but I could be wrong
Also, the flaring: It could be that they just don't care, but my personal opinion is that the large, heavy and frankly excessive finnage of some of the modern fin types is such a strain to haul into full flare that the males are disinclined to do it. I've noticed that of my bettas those with less fins are more flare happy. But that COULD be because there has been less stuffing around with them by humans and therefore they exhibit more natural behaviors. I don't really know.
And walking past pet stores? Aquabid is a pretty good cure for the urge to collect... one day on there and you see SO MANY you want that you despair of ever having enough space. As for OMG! Those poor bettas dying in those tiny cups! I have to save them! - Well, that never really goes away. If anything, it gets harder the more bettas you have because you know how incredibly diverse their personalities are and to see so many with nothing better to do than float listlessly at the top... yeah, it sucks. I suggest keeping away from pet stores. Or else getting more tanks.
