Monkfish - which are actually also known as anglerfish - are quite common in the English Channel. They are fast predators which can be up to 1.5 metres long. It is said that a monkfish's head usually weighs over 50% of their total weight. Monkfish are known for their terrifying appearance and flat body. Most of the time, they lie on the seabed to hunt but make occasional trips to the surface, according to the Cornwall Wildlife Trust. The fish, a silent predator, is also known as the 'sea-devil', said the trust.