Whats wrong with my shrimp?

Brief：
Ive had a banded coral shrimp for about 3 months. He has always been very active. He moves around the entire tank, climbs the walls, jumps off the roc.. 

I've had a banded coral shrimp for about 3 months. He has always been very active. He moves around the entire tank, climbs the walls, jumps off the rocks, and dives for food when I feed him. I recently added a high wattage light, for coral, that has a night setting. Since I started using the low light at night, my shrimp hides under the rocks all day. He's always out in the morning, but instantly retreats when I turn the light on in my room, let alone the tank light. When I'm able to get a good look at him, he has brown furry stuff on his legs. He was never bothered by lights before. Is my light too bright? Is he sick? or is he naturally nocturnal and just never had a chance to show it since the lights were always on?

After being in a steady environment for over three months and then changing it, especially the lighting it will throw off the natural cycle or what the shrimp has adapted to.which means it just has to adapt again. good luck? Try total darkness for at least two weeks check daily with black light Sounds sick to me. Try doing a large water change and consider adding a bit of iodine.

A