The sight of hundreds of dead fish along the shoreline of Nanakuli Beach park and out to Maili made more than few people worried.
Click here to watch Catherine Cruz' report.
"I'm very concerned, because its an unusual type of occurence and we don't know if it's environmental or caused by man," said Waianae fisherman Randy Iaea.
Iaea said he got even more worried when he heard that his friend saw them washing up at Kaaawa this week too.
"When I shared the pictures he was expressing some concerns too. Like wow, what is going on?" Iaea said.
State biologists began collecting samples near Koolina and along the south shore when the reports began coming in on July 1.
Test results wont be known for a few weeks but they believe the dead fish are what some people know as flying gunnards.
They are a different species from the malolo or regular flying fish.
The gunnards have long fins but they glide underwater and don't actually fly above the surface.
Biologists suspect that the fish kill may be related to a spawning cycle around this time during the summer.
rather than something toxic in the water.
"If it was a chemical spill of some sort than you would see many species dying off." said Alton Miyasaka. a biologist with the State Land and Natural Resources.
But the mass die-off is a bit of a mystery.
"We don't know specifically what has caused this particular die off. We have seen these kinds of die offs. Its not an unusual but its not common, but we have seen single species die-offs before," said Miyasaka.
The public is being asked to report any sightings of dead fish to the Eyes of the Reef Network, which in turn is alerting the state.
"We are keeping track of the reports coming in and trying our best to respond to them and get fresh samples so we really appreciate the help," said Anne Rosinski, marine specialist with the state Division of Aquatic Resources.
Once the test results are in, they will be posted at the reef response website of the Department of Land and Natural Resources. But if you see any more of these dead fish in other areas, do report it.