Allow to marinate (soak) for at least 4 hours (overnight is really good).
Add oil to your frying pot and heat to 350°F. In a large bowl add the flour, onion powder, garlic powder, Creole Seasoning and black pepper and mix with a whisk.
Soaking the frog legs really helps soften the meat before frying. If you can't get the injectable marinade then milk or buttermilk is a good alternative.