Did it turn to mold or did it just get waterlogged and fall apart? Try a piece of zuchinni. I just put a cup of water and bring it to a boil in the microwave and drop a piece of zuchinni in it for a minute. Then I take is out, run it under cold water to cool it off and stop the cooking process and put it in the tank with a veggie clip. They love it!
Put the frozen peas in a couple of inches of water. Microwave them for about a minute. Peel the peas by squeezing them, then drop the insides in the tank. Sometimes I smoosh (great word !) them in my fingers for the smaller ottos. Good luck ! (Ottos aren't the only ones who like peas !)
I have found that my Otos will eat "snail jello". The recipe is on a sticky in the FW Invert section. The flavors they prefer are either organic first peas, spinach, or green beans.