They might just be full. Fish arn't that stupid just because something doesen't taste good to them doesen't mean there going to turn it down if there starving! Blanched cucumber is usally my fav choice when it comes to suplimentary feeding. I have never had problems with fish avoiding food because of taste. Well my von rio wasen't fond of flakes after I was feeding them blood worms for a while, but he eventually came around when he got hungy enough.