Fish too look after their mates!

Sydney: When it comes to helping each other out, it turns out that some fish are better at it than previously thought as researchers have found that pairs of rabbitfish cooperate and support each other while feeding.

While such behaviour has been documented for highly social birds and mammals, it has previously been believed to be impossible for fish.

"We found that rabbitfish pairs coordinate their vigilance activity quite strictly, thereby providing safety for their foraging partner," said Simon Brandl from Australian Research Council's Centre of Excellence for Coral Reef Studies.

"In other words, one partner stays 'on guard' while the other feeds - these fishes literally watch each others' back," Brandl said.

"This behaviour is so far unique among fishes and appears to be based on reciprocal cooperation between pair members," Brandl noted.

Reciprocal cooperation, which requires an investment in a partner, which is later reciprocated, is assumed to require complex cognitive and social skills which fish have been deemed not to have.

Yet, Brandl said their research showed clear coordination and presented intriguing evidence for reciprocal cooperation between the rabbitfish pairs.

"There has been a long standing debate about whether reciprocal cooperation can exit in animals that lack the highly developed cognitive and social skills found in humans and a few species of birds and primates," Brandl said.

"By showing that fishes, which are commonly considered to be cold, unsocial, and unintelligent, are capable of negotiating reciprocal cooperative systems, we provide evidence that cooperation may not be as exclusive as previously assumed," Brandl noted.

The findings appeared in the journal Scientific Reports.