ive got an african arowana that never sits still... however the same can be said for the goldfish that somehow managed to never get eaten and is now pushing 3"..
My emerald cories hardly ever sit still. They're completely spastic. They line up and cruise the top of the tank, making a little wave... Actually, most of the fish in my 125 community are like this. It's the most active tank I've ever seen. Sometimes, it actually annoys me... I mean, the lights are out, and they should be sleeping... nope. All 55 of them are swimming in completely different directions.