Mozart's favorite color is white, if there is anything white out the tank he eyeballs it, going up and down. Even a cat Delilah.
The other day I got a thermometer and the suction cup broke (brand new btw) so it floats in Mozart's tank, he swam up to it and touched it his his nose. The thermometer bounced away a little, then he hit harder and watched it bounce further away.
Not just cute but smart! He knows when I lift a little door on the lid that he's being fed and swims right to the top before I even put the food in, same place each time.
I didn't know you can pet them! Though I don't dare to try.