Some people may find the citywide hunt for what they perceive to be harmless exotic fish unnecessary, but perhaps they will change their minds when they come face to face with a 1.7-metre lizard in a country park or man-eating piranhas in a pond. On Friday, 16 alligator gar - fish native to North and Central America - were found in artificial ponds at four public parks, presumed abandoned. Government workers began removing the fish, yesterday catching another 17 in five parks: Tak Wah, Chai Wan, Hong Kong, Tsing Yi and Lai Chi Kok. Some park workers and members of the public decried the action, saying the fish had become their friends. But the alligator gar are just some of the abandoned animals that once enjoyed comfortable lives in Hong Kong flats - until their owners decided to turn them loose. Lizard-lover Yiu Chi-ho, who owns Reptile Corner in Causeway Bay selling exotic snakes, tortoises and lizards costing from a few hundred to tens of thousands of Hong Kong dollars, saw a 1.3 metre iguana by Shing Mun Reservoir in the New Territories. 'These lizards are from South America,' he said, 'so the only way it could have got there was because someone chose to abandon it.' Yiu said that while not all imported insects and reptiles were poisonous, they could potentially attack people if they became hungry. 'Normally these lizards are docile, and many of them are vegetarian,' he said, 'but after a few years in the wild they may become aggressive.' Two years ago, a metre-long ball python was removed by the department when spotted in Kowloon Park, Tsim Sha Tsui. And in 2004, a 14-year-old boy's finger was bitten when he put it in a pond infested with piranhas abandoned by a fish owner. In response to criticism over the removal of the alligator gar, Florence Hui Hiu-fai, undersecretary for home affairs, said yesterday that the species was considered one of the 10 most vicious fishes, and while it might be harmless to humans, it would threaten a pond's ecology. It can grow up to three metres in length, and has a long sharp-toothed snout. The fish are commonly sold for home aquariums when they are less than 30cm long. The Agriculture, Fisheries and Conservation Department receives abandoned animals and arranges for their adoption, but the overwhelming majority are cats and dogs. Exotic animals can be taken in too, but generally they are put down if no organisation is willing to take them. Society for the Prevention of Cruelty to Animals spokeswoman Rebecca Ngan Yee-ling said the society did not keep unusual pets because it lacked the expertise, and because it was almost impossible to find people to adopt them. However, such pets have gained popularity over the years. Yiu said a larger supply had pushed down the cost, and because people such as students could now afford them, there was the potential for more to be abandoned. 'I knew two middle-age women who were only interested in small lizards, so when they grew up they abandoned them on the hillside, and they would then buy another smaller one.' He said some people tried to sell these pets to shops when their families complained, or the pets outgrew their cage or tank, but some of these pets were already deformed from being in a cramped environment. 'We saw geckos whose vertebrae were all twisted, and tortoises whose shells looked like water chestnuts because they only had space to grow upwards.' Owners of exotic pets must have a purchase invoice and an import permit code. Importing protected species was prohibited, except in special circumstances, Yiu said.