I participate on a few other science related forums. As you can imagine, it does bring out a lot people with Against The Mainstream (ATM) ideas, and these are generally welcomed, if and only if the poster will actually try to discuss the points they make rationally. Here is a copy and paste for the rules about ATM and conspiracy theory ideas (taken from the Bad Astronomy and Universe Today (BAUT) forums,
http/www.bautforum.com/showthread.php?p=564845 ):
13. Alternative Concepts and Conspiracy Theories
If you have some idea which goes against commonly-held astronomical theory, or think UFOs are among us, then you are welcome to argue it here. Before you do, though READ THIS THREAD FIRST. This is very important. Then, if you still want to post your idea, you will do so politely, you will not call people names, and you will defend your arguments. Direct questions must be answered in a timely manner.
People will attack your arguments with glee and fervor here; that's what science and scientists do. If you cannot handle that sort of attack, then maybe you need to rethink your theory, too. Remember: you came here. It's our job to attack new theories. Those that are strong will survive, and may become part of mainstream science.
Additionally, keep promotion of your theories and ideas to only those Against the Mainstream or Conspiracy Theory threads which discuss them. Hijacking other discussions to draw attention to your ideas will not be allowed.
If it appears that you are using circular reasoning, depending on long-debunked arguments, or breaking any of these other rules, you will receive one warning, and if that warning goes unheeded, you will be banned.
As with the other sections of the forum, we ask you to keep your topics about space and astronomy. We will close down any thread which doesn't have anything to do with space and astronomy immediately.
(emphasis and underlining mine)
With the proper modifications, something similar could easily be adapted to the fish science forum.
The big points are the ones I underlined and bolded. The bolded part basically says: Claims/ideas/theories have to be backed up by some semblance of fact. Evidence has to be cited, and direct questions that have direct answers need to be answered in a timely manner or the claims dropped. If you browse through the BAUT forums, the policy has worked pretty well there. If someone comes up with a new idea and they haven't done any math or science backing up their ideas, the thread is usually closed pretty quickly.
The underlined part is important too, and I personally have ran into this on this forum. It was a while back, but the most dramatic example of this was when the first poster wanted to use grapefruit seed extract in her tank. When I posted how when the scientific studies were performed there was no effect, that in fact the preservatives added to the grapefruit seed extract were the agents killing the microbes, she was pretty unhappy but still unbelieving. When I told her to go read the papers herself, she thought I was insulting her intelligence. I was just trying to show her that it wasn't just me, but the actual scientists doing the research that thought grapefruit seed extract was bogus.
I can see this set of circumstances happening again, so people need to be warned that the scientists are not going to openly embrace any new ideas that anyone might post. The wording "attacked with fervor and glee" is particularly good, I think. Knowing myself and this is evident in my post history, when facts support one point of view and there is little or no facts on the other point of view, I can be very resilient in not letting it go. You may call it something else, but I feel like all I am trying to do is get the other person to use some critical thinking skills of their own. I am trying to get them to see why a website posted by the manufacturer of a product is not the most trustworthy of places to get your facts. etc. etc.
Finally, it is a great idea to have a FAQ of what science terms mean. For a while now, I have been collecting articles on techniques on how to talk with "the man on the street" about science and I think I have some very good ideas on how to present that. So, on that note, I volunteer to help write up such an FAQ if (hopefully) TFF launches a fish science forum. Frankly, if there is anything else that needs to be done to get this launched, I'll volunteer to help with almost anything to get this started.