In the middle of the city there is a average size pond called Valkeinen. It is perfect place for angling because of its large variety of species.
Large roach maybe hard to find, but perches from minimal to >1kg. Breams are also hard to locate but Tench (700-1500g), crucian carp (even 1-2kg), rainbow trout (about 1kg), whitefish (not easy catch from coast) etc etc... There have been caught >10kg pikes too and some rumours are about carps (5-7kg), but these are rare.
Let me know more about yourself (e.g. private message), if there is some extratime, I may have time to guide you.
There are several other places too that are worth of trying, but this Valkeinen is absolutely easiest location. Are you working at the university?