I have and iPod touch 4th Gen. I got it when it was first out and it is 8GB. However whenever I use it, the Battery goes down to less than 20% in the First hour. This makes me very annoyed. How do I fix it?
The 4th generation iPod touch was produced in 2010. Dependent on usage it's possible that the battery has lost its capacity. This is more or less normal battery behaviour.
You can get the battery replaced, or if you have premium quality DIY skills you can replace it yourself.