Lead author Jianghong Liu said that they are looking at Omega-3s coming from food instead of from supplements.
The team analysed 541 children aged nine to 11 in China.
About 54 percent boys and 46 percent girls completed a questionnaire about how often they consumed fish in a month, with options ranging from "never" to "at least once per week."
They also took an IQ test, which examines verbal and non-verbal skills such as vocabulary and coding.
Later, their parents answered questions about sleep quality using the standardised Children Sleep Habits Questionnaire.
Those whose meals sometimes included fish scored 3.3 points higher.
Adrian Raine explained that lack of sleep is associated with antisocial behaviour; poor cognition is associated with anti-social behaviour.
They explained that Omega-3 supplements reduce antisocial behavior and it's not surprising that fish is behind this.
Pinto-Martin stated that fish consumption has really positive health benefits and should be something more heavily advertised and promoted.
For the moment, the researchers recommend incrementally incorporating additional fish into a diet; consumption even once a week moves a family into the "high" fish-eating group as defined in the study.
The research appears in the Scientific Reports journal. (ANI)