ABSTRACT
Some fishes were thought potentially able to absorb nutrition. But, of course, we know that all fish eat to survive, as do all living things in one guise or another. However, a number of Britain's freshwater fish species do not eat as adults, or at least during certain phases of their adult lives. In our consideration of the life cycles of Britain's freshwater fishes as they become free-swimming, we have already observed their early dependence on essentially similar food sources, particularly small invertebrates. Many of the smaller cyprinids and other species may even start with food items that are smaller still, such as single algal cells. As freshwater fishes develop through larval and fry stages into progressively larger and more clearly differentiated juveniles and adults, they become progressively more dependent on the diets to which they are adapted.
