Yes, I just slice it and throw it in the pond. The plecos come up and usually attach to the bottom of the slice and just float around. Occasionally they will get it just right and be hanging vertically in the water but not often. They don't like the lettuce that I throw in for the cichlids but they can smell that zucchini immediately. Mine too suck out the middle of the slice and leave these floating circles of zucchini skin, if I leave it in there long enough the cichlids will eat the skin.
I got a small type of pleco for the roof pond. I put it in a small fountain pond I have on the terrace first as a quarantine. The dogs drink out of that fountain and although I never saw the little pleco come out from under the rocks, it was gone when I cleaned the fountain
I'm afraid one of the dogs may have slurped it up. I felt responsible and now I don't want to get another. The other thing is that I worry about introducing something into my ponds so I very rarely add any fish and if I do I isolate them for weeks first.
Those baby albino catfish are precious. It would be really cool to have a tank with babies. My problem is I want all the pretty fish and they don't all get along or can handle my conditions. I really wanted some Discus but they just can't handle the hard water we have.