My plecs love zucchini, but won't touch cucumber, yet. Side note though. I bought three terrarium plants for my newt tank, but they were all too big. I wasn't sure if they could survive being completely submerged so I stuck them into my 55 gallon. 2 of them had to go, but one looks like it's going to make the transition to aquatic. However, my yoyos LOVE that plant, eating it that is... One of them has doubled in size since I put it in there. They love to lay in the uncurling leaves, and then when the leaves open a certain amount, it's eating time! I wish I knew what kind of plant it is, but it had no label and the name was not listed on the receipt. They do not eat any of the other plants in the tank.
Take care,
Mary.