Filefish (Monacanthidae) have a very characteristic appearance, but whether one likes them or not is a matter of taste.
Some species are suitable for aquaria, although they will occasionally eat a coral or invertebrate. They are therefore not so well suited to coral tanks.
They are often used to fight glass anemones (Aiptasia) and Majano anemones. Pervagor nigrolineatus is especially good at this.
They need peace and quiet from both the aquarist and other fish, when adjusting to the tank life.
Be careful when catching them, as they easily becomes caught in the net.