Plecs need veggies 2-3 times per week, and wafers in between as a supplement - and depending on the species - omnivores (BNs) need some protein, carnivores (snowball) need less veg (I'm not 100% sure but I doubt they'd eat much - so that's leaving them with only plec wafers - which aren't "meaty" enough for them either), and royals (herbivores) need bogwood as the main part of their diet, and then veg, wafers being a supplement to all. It's not a very good combination of plecs for feeding purposes as royals should have little/no meat in their diet, whereas the snowball needs it. It would be best to have the royal in another tank as if they eat too much protein it can dramatically affect their health. Unless your tank is large and you can feed at opposite ends of the tank - then clean up any left overs. Either way, 4 plec wafers 3 times a day is excessive and will only pollute the water, and your snowball needs a meatier diet - shrimp, squid pellets, bloodworm etc - things the royal shouldn't be allowed to get to.