For fishers Manamansalo is a real gem. Oulujärvi is very multifaceted lake and the best places to catch a fish are revealed in a booklet, which are sold at Manamansalo camping area reception. You can buy the permits from reception or from the automate at the gate 24/7. There are also rowing boats for rent. In Manamansalo fishing area there are five clear watered ponds where are naturally grown whitefish, pike and perch. Furthermore, there are regularly planted rainbow trout! The area is offering almost limitless possibilities for fishers!
For more information, read this (in Finnish and Swedish).