I read this interesting article
on the National Geographic website about these fish that can actually live outside of the water for months at the time. The fish is a mangrove rivulus or mangrove killifish and as its name suggests it lives in the swampy mangrove forests. When the mangrove swamps dry up during dry periods the fish simply lives in logs under piles of damp leaves. It can do this for around 66 days breathing air through its skin whilst still retaining its gills. Amazing.