From a more practical point of view, when you create more specific sub-groups, the traffic in each declines. Experts who focus in on one section don't visit the others, and so don't share their information. For those that want "all bichirs, all of the time", there are bichir forums out there. Ditto puffers, arowanas, and the rest. But the good thing about this forum is that different people talk to each other, "cross pollinating" along the way.
To take an example: I was one of the people who advocated a Rare Livebearers sub-group, where people keeping halfbeaks, goodeids, and the rarer poecilids could talk without having to wade through dozens of posts about guppy fry. We now have the Rare Livebearer group, and while small and quiet, it's useful for those into this type of fish. But, one the downside, the Common Livebearers sub-group has felt the loss. With fewer experienced aquarists stopping by, the newbies who have found guppy fry end up talking to themselves (heaven forbid they should read a pinned topic!). I make a point to visit the Common Livebearers sub-group, and so do some of the other experienced livebearer keepers, but still, the loss of talent and experience is palpable.
So, while creating a sub-forum has been good for me personally, it's probably bad for majority of aquarists wanting to learn about livebearers.
Cheers,
Neale
