Authorities are investigating whether negligence at wastewater treatment plants was to blame after millions of fresh water fish locally known as "popocha" began to float up in the Cajititlan lagoon last week.
Some 130 fishermen from the town of Tlajomulco continued to pull dead fish out of the water on Monday and buried them in pits, removing some 53 tons so far, according to the Jalisco state environment agency.
"We don't want this problem to worsen because we would end up in the street," said Rigoberto Diaz, a local fisherman who fears that other species such as tilapia, which unlike popocha is edible, will die too.
Fellow fisherman Mauro Hernan echoed concerns that authorities have yet to confirm the cause of the die-off.
"We were told that the state government will support us. We don't know when we will be able to fish again," Hernan said.
Jalisco state environment secretary Magdalena Ruiz said it was the fourth unexplained fish kill at the same lagoon this year.