You are probably feeding them too hard. If there's too much nutrients in the water, they can't take up any. I'd back off to like 700 PPM for a little while and see what happens. But they definitely don't look right, thats for sure. Hopefully someone will be a little more help than I was, but I would lower the PPM. As a rule, I never go over 1,200, and rarely over 1,100. I run mine around 900-1000.