I do see where you are coming from, but the point still stands- when will the division end? It's the picking over the small points and ignoring the larger ones that is annoying- was there any real need for the livebearers section to be split? Maybe, but what of other sections where splitting is much more important? The generalised 'Cyprinids and Characins' section, for instance, is one forum where splitting is actually useful- all catfish are catfish whether they're plecs, cories or 'other', but Cyprinids are not Characins, and those two groups are probably the most widely kept of all fish. You can split the forum until the cows come home, but whether any of it actually has a point or not is debateable. The forum is difficult to navigate for some people as it is.
The main reason I am against this is in the intrests of fairness to other fish groups. While everyone who has posted here is 'interested in finding out more', I bet if you posted a thread saying 'Can we create a seperate forum for all fish with an adult size of under 15mm' or 'Can we have a seperate section for large catfish with an overall black bodycolour with less than 15% other colours who eat small Jack Russels for breakfast and live in medium sized stagnant puddles in Outer Mongolia' you would still get people saying the same. If people are really that interested, then why aren't there more posts about them? The person wo can't even spell a few posts back said ' Killifish have interested me for ages, but i have found very little about them on this forum (as you have stated)'. Bullrock said 'I would like to know more about them, too.' Someone else said 'I personally have always wanted to learn more about Killifish'. So if these statements are true, then why are these people not actually asking about them? More instances of wanting to be spoon-fed information.