First, dude, they're not fish.
Second, don't feed them freshwater items. Try raw frozen shrimp, raw scallops, stuff you can buy at the grocery store or fiddler crabs, frozen silversides, krill, etc. Saltwater items. Feeding freshwater items will shorten their already short lifespans, not to mention fish stores typically treat their fish tanks with copper. Copper treated fish is VERY BAD for octopus.