Zucchini works better that cucumber (imo).
Core the seeds out of it and if you buy organically grown leave the skin on it.
If you do not blanch it then they will work on it for about 3 days before it turns to mush in the tank. Blanch it and 24hrs later it starts making a mess.
Day old raw zucchini works well for little ones here.
Algae flake (not wafers) too.
Algae Flake I purchase here.
Romaine Hearts work well for Ancistrus and Otto alike.
congrats on the spawn and good luck