Longnose Gar are predators to multiple organisms.  When they are young, they eat small crustaceans, like cladocerans and copepods, and insects, like mayflies.  Their diet switches to fish.  Some of these fish include sunfish, blue gills, smallmouth bass, largemouth bass, black crappie, catfish, and many more.  Their sharp teeth allow them to eat pretty much anything that fits in their mouth.

Longnose Gar no major predators.  Their scales provided excellent protection against every other fish.  They have been seen being attacked by American alligators.  Although, research points towards these being opportunist attacks.
    To see a great image of an American alligator eating a Longnose Gar click here.

The Longnose Gar are hosts to the yellow sandshell.  Without the Gar species, this species would go extinct.

Longnose Gars don't interact with humans too much.  The Longnose Gar is seen as a nuisance to commercial fisherman because they get trapped in fishing nets often.  Since they eat a lot of game fish, their not very popular with people in general.  Although, the gar has been used to help keep sunfish and yellow perch population in check.  People also use their scales for decorations on things like picture frames and purses.