Keep in mind any fish works with this recipe, not just gar. The fish balls can be made ahead of time and frozen. Make the gravy when you are ready to serve them.
If you have a meat grinder, grind the fish through a fine die (4.5 mm). If not, dice the meat and pulse it in a food processor until it's ground, but not a paste. Or, if you have indeed scraped the fish off the sinews of a large gar, mince that by hand.
Mix that with the green onions, parsley, celery, jalapeno, Cajun seasoning, breadcrumbs and eggs. Mix well so you can make balls out of it. If it's too wet, add breadcrumbs. Too dry, add another egg. (It's rarely too dry.)
Dust the balls in the fine cornmeal or flour and fry them in batches in 350°F oil until golden brown, turning them so they cook evenly. This will take about 4 to 6 minutes. Be sure to let the oil temperature return to 350 before frying the next batch.
Let them cool on a rack set over a baking sheet. At this point, you can refrigerate or freeze the gar balls for later.
GRAVY
Heat the butter in a medium pot over medium-high heat. Stir in the flour and cook this, stirring often, until the roux turns at least the color of peanut butter. I like to cook it until it's the color of milk chocolate. This can take more than 15 minutes, depending on your heat.
Add the onions, green pepper and celery and cook this, stirring often, about 5 to 8 minutes. Add the garlic in the last couple minutes. Sprinkle on the Cajun seasoning.
Slowly pour in the stock, stirring constantly. Add some, incorporate it into the roux, then add more until you have a gravy with the consistency of melted ice cream. Add salt, Worcestershire sauce and hot sauce to taste. Heat up the gar balls in this and serve over white rice.
Notes
If your Cajun seasoning doesn't have salt in it (most do), add 2 teaspoons of salt to the gar balls.