Is this tail rot?

[LLazyLizard]

So I've had my bearded dragon for about two months now and I've noticed his tail is kind of dark - the color starts fading around the halfway point and by the tip of his tail it's gray. Does my beardie have tail rot? He can still move it fine (he wraps it around my arm) and he doesn't show signs of pain if I squeeze his tail. I might just be paranoid, but I want to make sure he's okay.
He's about a foot long and lives in a 40 gallon tank. His basking spot is around 100 degrees Fahrenheit at the hottest and he spends lots of time under it. His UVB light is a 10.0 Reptisun and I think his heat lamp is a repti basking spot lamp? Not completely sure. He eats lots of arugula, watercress and kale (3/4 - 1 cup-ish?) a day and 10-15 mealworms. 1-2 days a week he gets crickets instead.

 

[RarestDragon]

Looks fine to me. Usually the tails are a bit dull in color, especially the last few inches. Kind of looks like it's getting ready to shed too.

 

[Sixxx]

Unless you can see a pure black tail/open wounds/missing tail, then it's completely normal. My dragon has the same and they usually grow that darkness off over time.