Why has my turtle stopped eating lately

I have had a red earred slider for about two years now, and within the past week or so, he hasn't really been eating much. Usually when I drop some turtle pellets in the tank, he eats them all within seconds. He has done this once before right after I got him, but I'm not sure if theres some particular reason for this.

Hi! You say you have a UV light? Does it say UVB? Or just UVA? It is very very important to have a UVA/UVB light that emits at least 5% UVB but 10% is better!

for the not eating, read this,

* Is the turtle kept warm enough? If turtles get too cool, they will stop eating.

* Does the turtle like the food you offer? Try out different foods. Some turtles can be very finicky eaters, especially in the beginning. And they have definite likes and dislikes. Most turtles will eventually take small earthworms that are wiggling in front of their nose. Start feeding favorite foods, then slowly introduce other items.

* Is your turtle exposed to too much stress? This is often a cause in new animals. Stress can be caused by handling, traveling, tank mates. New turtles will often not eat properly for several weeks. Be patient and keep trying.

* Is your turtle healthy? Not eating can be a symptom of other problems. If your turtle has been eating well and suddenly stops, a health problem is a likely reason. Take a fecal sample to your veterinarian. (Fecal samples need to be no older than 4 hours, and you need to store them in water in the refrigerator.)