yeah, it's a pity about neon disease, oscars must eat neon tetras in the wild all the time!I believe that have varied diet is healthiest diet for most fish, especially oscars. Isn't neon tetras a little unsafe feeder for most fish because of the neon disease? Your best bet is raising some livebearers (guppies, platies, gambusia and endlers), crayfish, cherry shrimp or convicts as you said you will feed him live fish once a month.