I expect in the near future to take my own pictures of these cool fish, but here is what I've found online.
(Photo found at this site).
Briancoad's website describes them almost as a link between fish and amphibians:
The swimbladder has a rich blood supply enabling the
fish to breathe air through a connection to the gut. A school of gars will break the water surface to breathe air at the same time and reduce the chances of attack by predators. Vertebrae are peculiar in having an opisthocoelous shape ...- which is almost unique in fishes and more usually associated with amphibians and reptiles.
The thing that makes them most interesting to me is their habit of sunning themselves in shallow water - really shallow. At a local beach, I chased and almost caught one in less than a foot of water (30cm)- and this was a fish close to a metre in length.
I've been having trouble seeing my own site. The Seoul Hero suggests a bad link or imbed for a photo. If you can read this, please leave a message -ah, before July 12th, let's say. Thanks.