Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Fish are like many other animals, including children: If they are presented with a new food they do not immediately know it is food, and may be reluctant to eat it.
Worms, on the other hand do not have whatever warning signal is involved in avoiding unfamiliar things, or else the zucchini resembled something else they were already familiar with, so they moved in on it.
Keep offering a variety of foods, and when you find something the Oto will eat you can put 2 of something on the clip: The food he eats, and something new, including other vegies or algae wafers.
Mine like the inside of a broccoli stem. The skin is a bit too hard, though.
Green beans, sliced lengthwise to expose the tender inside.