Does my betta have fin rot?

ive noticede that lately my betta is at the bottom of the tank in the afternoon each morning i feed him he'll eat falre for 20min then do it again then i noticed he had mini pinholes in his top fin hes a veiltail and is red and white he also has mini curve in on his fin is it fin rot and if so what antibiodics should i look for? hurry i dont want my betta to die....http://s1227.photobucket.com/albums/ee440/bettaknight10/