Dozens of bars, discotheques, concert halls and other night spots have shut down in the main Brazilian cities following more rigorous safety checks in the wake of last week's tragedy in the southern city of Santa Maria.
Police have linked the fire in the club to a pyrotechnic show launched by musicians using flares designed for use outdoors.
The two owners of the "Kiss" disco and two musicians have been detained. In Santa Maria and other towns in Rio Grande do Sul state, Carnival celebrations have been canceled as a sign of mourning.
In Rio, where nearly a million visitors are expected for the five-day Carnival extravaganza, which kicks off Friday, 127 of 209 establishments inspected by firefighters last week have been closed.
"They were shut down because of security lapses," fire department chief Sergio Simoes said.
Ana Carvalho, a spokeswoman for the Rio public security secretariat, said clubs which remain open must fully comply with safety rules, but conceded that authorities cannot "check everything at once".
Many young people, meanwhile, said they were fearful but still planned to have a good time and attend nightclubs during the festival.
"You think about it. When you arrive, you immediately look for the emergency exits," said 25-year-old Cynthia de Oliveira.
"It's absurd that it takes a tragedy like Santa Maria for clubs and theaters to be inspected," added 31-year-old Liliane Barbosa.
Simoes said 16,000 establishments, including restaurants and hotels, were checked last year. The goal for this year, he added, was to inspect between 40,000 and 48,000.
Club owners vowed increased vigilance.
"After Santa Maria, we are going to be extra careful with respect to safety," said Marcos Alvit, owner of the Melt disco.
He said he will close his 12-year-old club for two months after Carnival to carry out renovation work ahead of the 2014 World Cup and the 2016 Rio summer Olympics.
But Alvit said most club owners feel that "a witch-hunt has begun and that there is a certain amount of paranoia."
"We are not going to be able to resolve everything immediately," he warned.
Authorities and entrepreneurs both agreed on the need to cut red tape and the time it takes to deliver permits.
"We have to apply the law, which is strict, and create rational control mechanisms," said Rio state public security secretary Jose Mariano Beltrame.