First of all DON'tT give him feeders.. I know you probably heard this before and don't care BUT: You don't know the pain of realizing your fish has gotten parasites.
Secondly: Pure style feeding- Meaning that you feed the fish nothing BUT pellets for a while, and then eventually it has no choice but to eat the pellets.
1. Apparently you havent read the stickies about general gar care. im not sure how deworming fish is painful.. or treating parasites in general is so horrible... it happens. i deworm/ip my fish every 6 months and QT and treat any new fish.
2. not only will some fish refuse pellets but they can and will starve to death.
take my advise or not but ive kept gar successfully for more then 2 yrs now, and fish in general over 20 yrs. Ive gotten nothing but great advise from people here. particularly the ones who wrote the stickies.
might i also add gar are piscivores, this means they are fish eaters. live fish are their natural diet, they do not suffer from thiamine issues as cichlids and other fish species do. At least not ime, or any scientific publishments. Other then how feeders are kept poorly( yes they can carry parasites, and diseases but any new fish introduced to a tank can, which is why it is advisable to have a QT tank setup for feeders.) and personal morals.
I dont see much if any difference feeding my fish live opposed to fillets from the market ( btw the crap thats fed farmraised fish is as disgusting as what feeders are often raised on) feeding live they also get the internal organs and bits fillets do.
read threw the stickies if you havent yet, there are some good suggestions for transitioning gar.
it also sounds to me like hes getting bullied, i honestly think hed readily eat pellets if the other tankmates wherent so food aggressive. you may try feeding the tank... then doing so again a lil while later after the pigs have eate.