Hikari and others are available online.
You might look into alternatives, try a feed store and ask about catfish chow or cichlid chow. It needs to be fresh which means they need to sell it fast. Bulk feeds loose their nutritional value quickly and the fat, to aid digestion, goes rancid pretty fast. Don't buy greasy bags.
Also, you can't allow it, or other food bought in quantity to get old at your house. To keep it fresh it needs to be frozen. Not refrigerated, FROZEN. Keep whatever you'd use in a matter of days, out, stored in a resealable container, and freeze the rest.