Complex sentence: In the deep, cold and relatively acidic deepwater ribbon lakes they favour, natural food is not plentiful and they eventually reach a terminal size where energy expenditure in pursuit of food cancels out any surplus that to that point had contributed towards growth.
Split into simpler sentences: In the deep, cold and relatively acidic deepwater ribbon lakes they favour natural food which is not plentiful. They eventually reach a terminal size where energy expenditure in pursuit of food cancels out any surplus that to that point had contributed towards growth.