Can Eels Change Colour?

Yes, they can and they do throughout their lives. Their backs may be black, brown, green or grey and young eels are usually dark on their backs and sides but yellow underneath. They are usually known as yellow eels, rather predictably, at this stage of their life cycle.

As they grow in the freshwater rivers in which they developed as larvae, the young eels grow – the females reach a metre in length and the males tend to be smaller – about half the size of the females. As both sexes mature, they take on a silver hue and are known, again predictably, as silver eels during this stage.

As they prepare for mating and breeding, the eels build up a lot of fat and they are highly prized for food as they can weigh up to 9 kilograms each. When they are fully mature adults, they take on the usual dark brown or black colouration and remain that colour for the rest of their lives.