Does the Bible say for sure that Daniel was a eunuch? Now God had brought Daniel into favor and tender love with the prince of the eunuchs.
  (Dan 1:9, KJV) 


The prince of the eunuchs is the guy Daniel asks for permission to eat the pulse and water instead of the king's meat. This seems to indicate that Daniel was a eunuch, because the prince of the eunuchs was the person that he asks. This is an important question because how we translate it gives credibility to how hard it would be if not impossible to be as great and for God as Daniel was.

Think about it. Guys are distracted by lots of things that wouldn't be as distracting, if distracting at all, if one was a eunuch. If Daniel was indeed a eunuch then in a sense he would have had a head start at being a man of God.
While the Bible does not say it, it can certainly be implied. It would be strange for him to not be. Unfortunately, since the Bible is silent about it, then that is about as close as we can get to it. But, I say definitely yes, he was a eunuch.