With about,com, ordersave, eHow and other Spam content continuing to rising to the first page with their crap
As well while I would not consider Fish Lore a spam website, it is a misinformation website with their bad information about the Aquarium Nitrogen Cycle, Melafix, and of coarse; Planaria. Sorry Fish Lore, these are not Planraria, rather Detritus worms and your link to the skeptical aquarist article further fuels this extreme misinformation
The facts are Google chooses which sites rise and fall in their algorithm (in part because these same sites appear in the discredited DMOZ which Google places a high value on), so this point from the Fish as Pets article still stand IMHO:
"If this is not a problem to you or morals are for someone else, go ahead and continue to use Google as your search engine or for other services"
Carl