I've gone thru this with several of my Veileds as they mature. Its like Carlton said he is growing up and possibly looking around for a mate. Green insects are a good appetite sparker. A lot of my Veileds started to eat vegetation about this time. Has he been chewing on his plant leaves? You could offer him some vegetation such as collard, mustard or turnip green, slivered squash or some berries and see if he responds to that or get him a Pothos plant to chew on. I use moss in my potted plants and lots of my Veileds and even some of the Panthers(not suppose to eat vegetation) eat it. None of them have ever had any problems. Get him outside for some good old fashion sunshine. Look for some insects outside. Stay away from beetles, ants and ladybugs. Try anything on him besides crickets, they have so many crickets tossed at them that they have no choice but to get bored with them. When they get moody and ready to mate they sometimes eat very little or not at all for a while. I wouldn't get too worried about him unless it goes beyond two weeks but do try to find him soemthing else for a change. Good Luck.