shekes said:You can't really know. Can you?
To me the Crenicichla Semifasciata is a lot more intelligent then the Oscar. But perhaps it is the Koi. The oldest lived to 206 years. Must have learned something...
My carp - black shark seems to have the ability to jump from tank to tank without even touching the glass. He jumps straight up a few times first. It looks like he is checking out the area from above before jumping sideways. That isn't dumb either.
guppy said:The one fish that I have kept that seemed smart was a large american eel.