Seconded.
You
absolutely do not need to feed spotted gar live foods. Quite the reverse. Once settled in they eat pretty much everything, from cichlid gold pellets through to chunks of oily mackerel. Strips of white fish and squid, mussel, and frozen shrimp can all be used as well. Basically, anything meaty and chunky. In the wild, these fish certainly do eat lots of small fish, but in captivity they are pretty much the easiest "tank buster" out there.
As others have pointed out, feeding live fish (at least, cheap "feeder" goldfish, guppies, livebait, etc.) is not just cruel but a high-risk strategy. If you want to keep a garpike just so you can feed it live fish, then
shame on you. There's no medical or scientific reason to feed a gar like fish any more than human need to eat live fish.
Moreover, once you have a fish feeding on a varied diet, and particularly taking pellets, then you can guarantee it will get a balanced diet with all the nutrients. Unless you plan on feeding your gar twenty different species of feeder fish, then you're not taking this precaution. It's critical to understand that keeping an animal in captivity properly is not synonymous with mimicking its natural lifestyle. We have to structure its diet more carefully in just the same way we have to design a tank to compensate for the lack of space and dilution of waste.
Cheers,
Neale
The alligator gar ate chicken hearts when I had him