While the fire tablet uses android. It’s amazons watered down version, to keep you in their ecosystem. Amazon has it’s own App Store. It doesn’t have access to the google play store and all the apps. Hence you can’t find it.
You will have to search the web, how to install the google play store on your tablet. Only then will you have access to ALL apps available for Android.
PikTV can be viewed on your browser. More information is located here.