You will need to provide them with plenty of cover for them to survive predation, especially in a pond with LMB. I am actually unsure of anyone having pellet trained YP so I'm interested in hearing thoughts on that as well. I'm sure it's possible, but like LMB, SMB, BC, etc, YP are predators and would tend not to take easily to pellets. As far as spawning, I'm sure you've seen the threads and PB articles regarding the type of eggs they lay. The word the experts use to describe it escapes me at the moment, but it's a gooey ribbon and I believe utilize vegetation for this, affixing this ribbon to the plants. More expert information soon to follow I'm sure. Oh, deeper water might be necessary too. YP like that colder water so they would need greater depths to escape warmer surface water during the summer.