Nah, fresh veggies every other day is good for those fish, as long as you are feeding some kind of protein on the inbetween days.
I'm not sure on the yams, but...
Yams if an unnuked slice were put in would be kinda hard for them, I would think. However, if nuked too much would turn to an oozing pile of mush in the tank... So maybe if you could find an inbetween so that they can still be sliced but be a bit more tender?
Again, I'm not sure on the yams idea. I'll try to remember to direct Dino this way.
