For example , the Devil 's Hole pupfish occupies only a single 3 by 6 metres ( 10 by 20 ft ) pool .
However , freshwater fish seem particularly threatened because they often live in relatively small water bodies .
The Devil 's Hole pupfish occupies only a single 3 by 6 metres ( 10 by 20 ft ) pool .
However , freshwater fish seem particularly threatened because they often live in relatively small water bodies .