I'm going to disprove one
Andrea, goldfish have longer memory spans than 3 seconds. I only know this because I graduated with a psyc. degree, and during my classes we went over a case where someone was able to train goldfish to follow a maze to find food. It took much longer than 3 seconds to train them, and they retained the knowledge. I think the "goldfish memory fact" is one of those urban myths that somehow got passed around (possibly through internet forums!).
Check out the "Behavior" section of this wiki article. The experiment was a bit different than the one I described, but the idea is the same.