Do i need anything else for a guinea pig ?

No, you need to get it a buddy.i had only one guinea pig(that i rescued from a school just as it was starting to develop scurvy) and it was so depressed bu itself that it started losing(alot) of hair and getting dandruff, and i mean ALOT of dandruff.Guinea pigs and rats are social/herd animals, and if kept alone(even with human interacton) can get depressed to the point of death.Most people think if they only get one, it will bong with them better.But actually the opposite.A guinea pig would get depressed if alone and turn aggressive twords humans.And no, btw half an hour wouldnt be long enough.