discus eyes

:? hi i have several discus in my tank .am im wondering if u could tell me why allsix of them have red in there eyes and looking front on at them there nice and thick in head.but the other one has dull eyes and no red in eyes.and very thin looking in front view at head.it has started to thicken up across the head in the last week .but has been eating fine and swimming around like normal.concerned

Most discus have red eyes, but they can have gold or even yellow eyes, so it's not that unusual. Sounds like he has been missing out on food. Hope he keeps improving.