Yeah, the cotyledons will die off after about a month from germinating. They exist only to give the young sprout a little jumpstart, and after the first adult leaves form and begin p[hotosynthesis the seed leaves aren't needed anymore.
Your plants look glossy, very nice. Weird color though- is that just the light?
You're going to want to give them some grow ferts soon. You have the first subtle signs of N def.