(CNN) -- Fish are washing up dead in Hawaii after a molasses spill in Honolulu Harbor.
Their colorful bodies bobbed on top of the water, video from CNN affiliate KITV showed. Workers scooped them into nets.
"It seemed like they were trying to gasp for air," Sachi Uehara, a resident, told KITV. "There were, I would say, over 50 eels that were up at the surface that we could see."
The Hawaii State Department of Health released a statement Tuesday warning people not to eat the fish and to stay out of the ocean if they see a brown color in the water.
A leak in a molasses pipeline could have caused as much as 1,400 tons, or about 233,000 gallons of the sticky stuff, to spill, the DOH said, citing representatives from Matson Navigation Company.
A Matson ship was loaded with 1,600 tons of molasses early Monday morning. It left Honolulu Harbor before sunrise, after which a discoloration of the water was reported.
The dark cloud is moving with the tides and currents from the harbor into Keehi Lagoon, where it is expected to dissipate into the ocean.
"While molasses is not harmful to the public directly, the substance is polluting the water, causing fish to die and could lead to an increase in predator species such as sharks, barracuda and eels," DOH said.
It warned the nutrient-rich liquid could also cause unusual growth in marine algae and trigger other unspecified environmental impacts.