Fishes can be very intelligent in fact. Many are more clever than mammals of its same size for sure.

They can do basically anything that a bird does, but underwater, and also a lot of tricks that we can't do.

There is not a single bird or mammal crystal transparent, or electrical, or bioluminiscent, or that could change their color at will in seconds. If I remember correctly, the vertebrates with the biggest brain/body weight ratio, or the fastest movement registered, are fishes.