A small tropical fish that has until now only featured in aquariums locally has been spotted in Maltese seas. 

Native to waters off Australia and Indonesia's west and north-western coasts, the small, beautifully coloured Azure damoiselle was seen in Marsamxett harbour last month in waters just two metres deep. 

Daniel de Castro caught the discovery on video and submitted footage to the Spot the Alien Fish campaign, which is coordinated by marine biologist Alan Deidun.

News of the discovery has been accepted for publication in a peer-reviewed academic journal. 

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Prof. Deidun believes the fish most probably found itself in local waters after being released from a tropical aquarium, though the possibility of it having been brought over to Malta after being transported in ballast water through the Suez Canal cannot be completely ruled out. 

According to Prof. Deidun, this is the fourth tropical fish species of Indo-Pacific origin first recorded in local waters by the Spot the Alien Fish campaign, following the yellow-bar angelfish, redcoat and silver-cheeked toadfish. 

In total, more than 80 alien fish have been spotted and identified in local waters. 

Fishermen, swimmers, divers and snorkelers who spot and photograph or record any odd-looking species can help scientists like Prof. Deidun keep track of the marine life living in our midst by getting in touch with the campaign via its website, on Facebook or by emailing aliensmalta@gmail.com. 

Photo: Wikipedia