Grumpy_Mike:
Just for one it will not matter, but if you must fit one then go for 10uF.
Thank you very much for your answer. So there's no risks of not adding one?, when I'm only using a single pixel? 
Grumpy_Mike:
Just for one it will not matter, but if you must fit one then go for 10uF.
Thank you very much for your answer. So there's no risks of not adding one?, when I'm only using a single pixel?