Contrary to earlier assumptions held by marine biologists, a new research study has shown that fishes are capable to forging cooperative relations among each other, the Sydney Morning Herald reports.

The new study has revealed that some pairs of fish keep watch over each other while looking for food.

Researchers from the ARC Centre of Excellence for Coral Reef Studies in Queensland conducted the study. The researchers discovered that pairs of rabbitfish guard each other while their mate forages for food.

Marine biologists have always believed that fishes do not posess a highly developed cognition and advanced social skills, that is required for cooperation.

Dr Simon Brandl, One of the researchers, said the fish co-ordinated their watchful behavior while feeding. They found that as one fish remained in a stationary, straight position in the water, the partner would feed itself. Also, the fishes with a partner looking for food take more "consecutive bites and penetrate deeper into crevices".

"This behaviour is so far unique among fishes and appears to be based on reciprocal co-operation between pair members," Dr Brandl said.

"By showing that fishes, which are commonly considered to be cold, unsocial, and unintelligent, are capable of negotiating reciprocal co-operative systems, we provide evidence that co-operation may not be as exclusive as previously assumed."

The team published their findings in the journal Nature Scientific Reports.

David Bellwood, who was also involved in the rabbitfish study, said their findings should inspire people to understand fishes as highly developed organisms with complex social behaviours.

"This may also require a shift in how we study and ethically treat fishes," Professor Bellwood said.