He is currently in custody being quizzed after a 14-year-old boy was knife at the weekend in Enniskillen, Co Fermanagh.
The knife attack happened at the Round O Jetty quay area just before midnight on Sunday.
Police say the victim was with another youth when they were approached by an unknown male who stabbed the boy twice in the abdomen.
The injured teenager was treated in hospital but the stab wounds are not believed to be life-threatening.
The attacker is described as wearing a blue/navy hooded top and black tracksuit bottoms.
Anyone with information is asked to contact detectives in the area on the non-emergency 101 number.