Well even the "experts" on the TV show MythBusters tackled the 3 second goldfish memory myth by buying two groups of goldfish and having a competition to see who could train their goldfish faster to get through a maze of plexiglass panels with portholes in them(in 2 identical 4 foot tanks) until they found their food at the other end. As they worked on this for weeks, going from first one porthole to eventually 3 or 4, yes the fish remembered it all from day to day, yes they ended up having goldfish races between their two tanks of fish to see who'd remember to do the mazes fastest. According to them, myth BUSTED completely. Goldfish have memories waaaay longer than 3 seconds. Actually so do all fish and the little blighters can see 25 metres...argh. Which explains why I can never sneak into the fish room without the Bettas seeing me and instantly pinning me with their "well, I'm here, FEED me" looks!
Bored? Well just look at ANY Betta sitting in it's little shipping cup in a store.... bored out of their minds! See them perk up once you bring them home, put them into a MUCH larger tank and give them plants to explore and swim through and snails to challenge
and room to swim about in. Add a guppy fry or two for them to chase madly and you've got a completely different fish on your hands.
Of course in a well planted and stocked community tank there's usually so much going on nobody gets bored at all. My 29 gallon looks abit like metropolitan Toronto sometimes...during rush hour...fish in all directions, all busy. The minute somebody finds a neglected shrimp pellet it's a scrum to see who can shove everybody else out the way.
Until one of the big corey mammas comes along and commandeers it by sitting on it of course!
The guppies get sooo mad at her but one of them trying to move her is like a Honda trying to push a tank.