What can cause a once hungry Castexi who was the last addition 7 weeks ago to stop eating. He was one of the biggest eaters in the tank, I left for 3 days and had a close fish fanatic friend of mine come over and feed my fish. I had all the food set up for him and he said everything ate while I was gone. I return home and my male Castexi is laying still in the back of the tank and doesn't eat anything when I feed the others. I check the water and this is what I got, pH 7.6 (always steady) ammonia 0, nitrite 0, nitrate 40 ppm, and temp. 82 degrees. I did a 40% water change and have been observing him. He just lays really still in the back of the tank. This is the ray I had to pick fish lice off of when I first got him. I have not noticed any lice on any of my rays or fish after I put him in the main tank from quarantine. I can't help but think he might have some lice on his belly, but I can't see it to tell. Any info would be awesome.