I put zucchini in for my royal pleco sometimes and a few of my loaches will usually eat some. They seem to click a lot when there is zucchini in the tank.
my clown loaches tear up any zucchini that i throw in the tank... just a note... it has been rumored that the cucumber seeds are too hard for must fish to digest and could possibly cause them to perish
Boil the zucchini for 1 minute it softens then so they sink better and peas are a feast for them too, make sure they are unsalted peas though. I wish I could find some other species of loaces here in Texas.