Ya, RC won't let me join either.. every time I have tried my account gets deleted within 5 minutes. Like they put a Ban on an entire IP range and anyone using an IP that falls within that gets their account deleted immediately by the board. So I don't have an account on that forum, nor do I really care to from their insane rules they put in place just trying to register. Still, the search feature and the front page/articles are very informative.
That link I posted is a great search tool for RC, it uses Google to search RC, not the built in RC search engine, which requires an account, and still sucks at searching.
That link you posted is ok for fish, but I prefer wetwebmedia for fish related questions.. corals, no real definitive site like there are for fish though.