Iranians have long celebrated Norouz and the arrival of spring by displaying live goldfish among the symbols of perpetual life on their holiday tables.
The elaborate still life, known as "haftsin," is ubiquitous in homes and at social gatherings around the Persian new year, which is celebrated this week, and comprises seven items beginning with the "seen" (س) letter of the Persian alphabet.
In another, increasingly perennial, rite, environmentalists and animal-rights activists urge Iranians to stop the "massacre" of millions of goldfish, including by freeing them at the end of the Norouz festival into rivers and ponds in which they are almost certain to die.
Many more fish perish under harsh conditions at markets and kiosks ahead of Norouz or at the hands of well-meaning but uninformed holidaymakers.
Outdoor markets in Iran this time of year routinely feature tanks and plastic buckets crammed full of goldfish that are sold off in plastic bags. The semiofficial Mehr news agency noted this week that many of the fish die in transit.
"Our seven-year research showed that these fish do not thrive once they are released into Iranian rivers and ponds except for very rare spots in the south of the country," Professor Gholamreza Rafiee of Tehran University's Faculty of Natural Resources, tells RFE/RL.
Activists say the deaths of so many goldfish flies in the face of Norouz and its accompanying theme of the rebirth of nature.
They've called on Iranians to use plastic goldfish or shun the tradition.
In what looked like a nod to their cause, President Hassan Rohani delivered his 2016 Norouz message beside a haftsin table that included an orange in a fishbowl in lieu of a goldfish.
But many Iranians resist the animal-rights argument.
"If we don't buy them, someone else will," Zoreh, a Tehrani mother of two young boys, told RFE/RL. "It's a tradition, and my boys look forward to it. This year, my 5-year-old boy insisted on going to the market with his father to buy our goldfish."
The seven primary haftsin items are apples, garlic, sumac, vinegar, samanu (wheat-germ pudding), sprouts, and oleaster. They are meant to symbolize life, love, abundance, wealth, and health, among other things. They are frequently complemented by objects including the Koran, coins, hyacinth, bread, and lamps or candles, and goldfish or representations of them.
To further complicate the goldfish debate, recent concerns about their inclusion have coincided with the appearance of a rare salamander in haftsin tableaus.
The so-called Luristan newt -- also known as the Kaiser's spotted newt or the emperor spotted newt -- inhabits Iran's western province of Lorestan but is listed as "vulnerable" on the International Union for Conservation of Nature's Red List.
Iranian media suggest there are currently only around 1,000 of the newts living in Lorestan, where locals dub them "colored lizards," although the IUCN itself suggests there are around 10 times that number.
The IUCN cites "uncontrolled overharvesting for the national and international pet trade" as well as "habitat degradation and destruction" as the major threats to the species.
Afshin Alizadeh, a zoology and wildlife professor at Tehran University, says the water-dwelling salamanders have become popular due to their peculiar shape and black-and-orange pattern.
"Due to its vibrant colors and body size, this species has found a great appeal in the market -- it is either a change in traditions and beliefs or a hankering for variety that has made some people choose to display the Luristani salamander on their 'haftsin' tables," Alizadeh said.
Speaking on March 10, Iranian lawmaker Mohammad Biranvandi even warned against the display of salamanders on haftsins, saying the practice endangers them.
"Unfortunately, some disregard the value of these rare species and use it as one of the 'S's of their haftsin, while people should not do that for their own pleasure," Biranvandi said.
He added that trading in Luristan newts is punishable under Iranian law.
Biranvandi called for tighter protection and awareness measures to save the salamanders.