I still have my smartest fish. Its a four year old Jack Dempsey that I've had all its life, this fish is amazing he can change colors with more definition and speed than anything I've ever seen. (and I had a chameleon! lol) If you change something in his tank he turns pitch black with just his speckles showing, when you feed him he strobes between colors of the rainbow, its amazing to stare at him for 5 minutes and see how much he changes during feeding time.
Of course I'm color blind so I can't give as much detail as I would like to. But friends and family are all amazed the first time the see him.