My corys have never been interested in the zuchini or greens and such I put in for the otos, but they went absolutely nuts over the raw salmon I dropped in last night.
Heh, spur of the moment idea. Trimming fresh salmon fillets, figured why not, can always fish it back out if no one eats it. Scraped the trimming with a knife edge to get little shreds, rolled it into a ball, dropped it in.
Gone in seconds.