No, a fish is not a mammal. Only a mammal has a backbone.
All Sharks are boneless. But they do have a type of skeleton, called cartilage. But they are not bones.
Most "regular" fish, such as the angelfish, have a skeleton made of bone (class osteichthyes, I think). Fish such as sharks, skates, and rays have a skeleton made of cartilage (class chondrichthyes). Even bony fish, though, such as your angelfish, have some cartilage for flexibility. I believe that the baby bony fish, like a human fetus, has pure cartilage until the bone forms. DL
No it is not, as you can see, the queen angelfish is much more colourful. The angelfish is just black and white. Except for the male, it is colourful but not as colourful as the queen angelfish.
There are not many fish that are compatible with Angelfish. Only Angelfish are truly compatible with Angelfish.
The angelfish is a breed of fish.
angelfish can be eaten by squids
Angelfish live in water. They do not get it.
angelfish mate in early summer
Angelfish release gas with their fins.
No, angelfish do not have lights on their heads.
Angelfish eat other fish.
Yes they can by a female angelfish after mating