Unlike most people would expect, scales lie under the epidermis. They are covered by a thin skin and mucus. The scale in itself is made of collagen and minerals so it has some nutritional value
This kind of fishes can take also a small chunk of the dermis or even the muscle.
The most interesting predatory strategy evolved in African lake cichlids is the "zombie fish". There are species of big fishes that lie motionless in the bottom over one side as if they were dead, they have irregular white patches in the corpse mimicking wounds. When other fishes came attracted by what looks like an easy meal, the corpse came to life again and strike