Now, I don't have a Rockhopper Tracker, but here are some good ways to find Rockhopper.
1. His favorite servers:
2. His favorite spots:
4. Don't listen to other penguins.
If Rockhopper was at another spot or server, they would be there too
They might not have his player card, proving they didn't meet him
HE IS NOT RELATED TO NORMAL CP PENGUINS, DO NOT LISTEN TO PEOPLE WHO SAY THEY ARE HIS SISTER/BROTHER/COUSIN/ETC
5. Don't give up, it's all worth it once you find him
After five hours + you can give up
An hour or two isn't the time to give up looking
6. Full servers
Rockhopper likes servers that have four or five bars
He also likes popular servers like Frozen and Mammotj
Hopefully this helps you find Rockhopper!