Instead of terrapins, birds or fish, some Buddhist devotees are buying small insects such as crickets to release into the wild during the Vesak Day period.
But releasing insects into the wild is no less illegal than releasing the other creatures.
At least two pet shop owners have told The Straits Times that more are opting for insects.
Buddhists such as Mr Richard Tay, a fengshui master at Fortune Resource Centre, said this is because it is easier to avoid getting caught. "Insects can be released anywhere, so some may do it as it is easier to avoid getting caught," the 59-year-old said.
Pet shop owner Darren Lee, 37, said more are snapping up crickets, though some still buy small fish for Vesak Day, which falls today. Some mark the festival to remember the birth, enlightenment and death of Buddha by releasing animals as a gesture of compassion.
"More people are buying crickets, and some customers tell me it's because their temples advise them to buy the insects instead," added Mr Lee.
The switch comes as the National Parks Board (NParks) ramps up education and enforcement to discourage the release of animals during this period. It is working with volunteers to patrol the nature reserves.
Last Wednesday, it warned devotees against releasing animals as doing so "does not guarantee their survival". Such animals could also "disrupt the ecological balance", it added.
NParks said in response to queries from The Straits Times that no animal release cases were reported during the Vesak Day period in the past two years.
First-time offenders caught releasing animals into the wild may be charged under the Parks and Trees Act and could be fined up to $50,000, jailed up to six months, or both.
But some devotees release crickets as they believe crickets are less likely to harm the environment.
Mr Benjamin Wee, 39, managing director of Petmart, said: "Crickets are smaller and won't impact the environment as much as other animals like birds, which could fight with other birds."
Insect expert Carl Baptista said the impact of the release of insects depends on factors such as the type of insects as well as the location and quantities.
"If it's a small number of crickets spread over multiple locations, it won't have much of an impact," he said. But if they are released in large numbers at a single spot, they may spark "a bird frenzy", when birds come to eat them.
But he did not think the release of crickets once a year will have a large impact.
Not all "liberate" animals on Vesak Day. Financial planner Marilyn Quek, 31, goes to a temple to "bathe a statute of Buddha" instead. She said: "I don't see the need to release animals."
In any case, Venerable Kwang Phing from the Singapore Buddhist Federation said the practice of animal release has been misinterpreted. He said: "You release an animal only to save it if it is in danger, and not order them from a shop to release."