Fish That Have To Stand On Their Tails To Eat
 

Personally, I have observed two types of cichlids that have to stand on their tails to eat floating food, as their body parts get in the way. Of course the Angelfish is one. If it didn't, it would have to stick its dorsal fin several inches out of the water. The male King Kamfa Flowerhorn has a hump (kok) so big that it's like having another fish living over its mouth, so it has to do a complete tail stand to get its jaws to the surface.

I'm sure there are more.Please feel free to write about any others.