knifegill;4542887; said:
Boil, no. It will just fall apart. Blanch it if anything.
What knife's getting at is - don't boil it for 20 minutes. 2-5 minutes at a rolling boil is fine so long as you're not using paper thin slices. When the center starts to go transparent, you're good in most cases.
Blanching is something done to fruits/veggies to soften/lightly cook/loosen & soften their skin. It's boiling followed by cold/ice water, just very short term. IE - Tomato blanching is very fast... 30-60 seconds to loosen the skins for sauce making. Zucchini takes longer to soften. The longer you boil anything, the less nutrients it retains. Steaming is a great option, but not as practical.
Think of it as "quick boiling", as to blanch, you're dropping it into a pot of boiling water for a short period of time.
Personally, my ottos get 1/8" sliced zuc that's been boiled for 2-3 minutes. They won't touch it otherwise - boiled shorter or longer. I raise such picky fish. -_-
If they don't ever eat it, try other veggies. My fish go nuts for the pre-cooked steampack brussel sprouts. Just thaw, and drop in. Be aware, they screw with water aroma like asparagus screws with your.... well, they'll make the tank smell like ripe brussels.
Red leaf, romaine, mixed greens, etc. Collards will need to be blanched in a lot of cases.