As a DM you are free (and encouraged) to tweak the game to your liking.
However, punishing players for their character building choices is bad. The player that made the halfling character probably had the option to choose another race with darkvision. Maybe not, but that is not the point.
There are several ways to mitigate the fact that one character cannot see in the dark. There are light sources, there are the goggles of the night wondrous item, and other magic or spells to allow him to adventure with his fey friends.
A torch costs 1 coppper piece, and solves the problem. Almost all starter packs have a few included.
I'd advise against changing the game too much in the first few games you DM. It is better to learn the ropes with the out-of-box game before making your own changes. But again, it is your game. Never let the rules get in the way of your (and your friends players) fun.
As @Erik pointed out in the comments, there are several races that suffer penalties in daylight. Most of them are native to the underdark (a huge underground labyrinth covering all the world) and these penalties offset some very nice perks they get. So you shouldn't just slap these other darkvision races with a penalty without some kind of benefit in another area.