Thanks for your comments guys- I did a little search and turned up some info on bowfin. If you are interested I've attached a URL and a couple of clips from the page on bowfin. The first paragraph seems to explain how I caught one - the pond it was in is a bay off of Lake Ontario. I know a fisheries biologist who says they are relatively common up here. The second paragraph describes the fish as being capable of gulping air. --My office mate told me a story about a bowfin he caught years ago- they landed it- got it in the boat where it came of the hook and slithered under the seat. The story goes that 4 hours later the fish was still alive - for all that time no one would reach in to grab it because it would slither out hissing at them! Sounds like a tough fish to me. Fortunately the one I caught was a bit more docile!
Millions of years ago the family Amiidae contained many species and had nearly a global distribution. Gradually members of this very ancient lineage became extinct until today only a single species, Amia calva, remains. Amia's distribution is restricted to North America, covering the majority of the Mississippi basin, extending east along the Gulf Coast, covereing the entire peninsula of Florida and extending north up the Atlantic Coast to the Pennsylvania/New Jersey section of the Delaware River. As with many North American aquatics, Amia migrated east through the Great Lakes and the Saint Lawrence River basin into Lake Champlain.
Amia is an easily recognized fish. It has a single continuous dorsal fin that runs from the mid-body almost to the tail. Amia's tail has a single lobe and appears to be nearly circular. There is frequently a black spot at the base of the tail near the dorsal edge. Amia has a rather large head with two barbels projecting anteriorly from its nose. Unlike most of the other fish Amia's swim bladder functions much like a lung, allowing this fish to gulp air when dissolved oxygen levels become dangerously low in the weed beds where it lives.