Also on the score sheet was Nigerian forward Daniel Chima who grabbed Molde’s second goal which was his first league goal after six appearances.
Aremu’s goal was his second in 12 league appearances for IK Start with his first coming in March in 4-1 win.
Etzaz Hussain put Molde 1-0 up on 23 minutes before Aremu drew IK Start level on 33 minutes.
Chima restored Molde’s lead as he made it 2-1 in the 53rd minute before Ruben Gabrielsen wrapped the three points for his side by adding the third goal on 88 minutes.
With the defeat to Molde, IK Start have now won just one of their last 11 league games so far this season.
They are now 15th on seven points in the 16-team league table while Molde are sixth on 20 points.