It's often referred to as brain food and now a study suggests fish could actually improve your concentration.
120 children from 23 schools across the UK took fish oil supplements for six weeks while their parents and teachers recorded their behaviour.
The results suggest that taking fish oil improved the children's behaviour.
Although the children that took part in the research took the Omega 3 as a tablet it can also be found naturally in oily fish such as trout and tuna.
Eating one or two portions a week of fish would also provide a similar amount of Omega 3.
Teachers reported that the primary school children who took the Omega 3 fish oil were more alert than usual and paid more attention in class.
William, 10, one of the children involved in the study was really positive about the supplement.
"I'm going to keep taking it as I hope it will improve my SATS."
Although adding fish to your diet is always a good idea there's no guarantee you'll actually notice any difference in the classroom.