The dead fish are appearing mainly on the north side of the lake. People who have lived on the lake for some time say they've never seen anything like it before and now the Texas Parks and Wildlife Department and the City of Houston are monitoring the situation.
This boat dock on the western shore of Lake Houston, Atascocita, is a sanctuary for Bette Kish and her husband. They've lived here for 18 years. But in almost two decades came a sight she's never seen before.
"I came out here and saw these fish floating. I mean there were a lot of fish floating. And I thought I don't know what this could be," said Kish.
She wasn't the only one alarmed. Just north of her neighborhood, another resident in Royal Shores of Kingwood also snapped these pictures earlier this week. A few snapshots show about a hundred dead fish floating along the banks.
Lake Houston is the primary source of drinking water for the Bayou City, another reason Kish was concerned.
"Everywhere I looked, I was seeing these floating fish and I thought, well I couldn't imagine what this could be and I thought maybe something had been released in the water that was killing the fish. That was my concern, especially since this is Houston's drinking water," Kish said.
We contacted the Texas Parks and Wildlife's fishery division. They tell us they are aware of the fish kill and at this point suspect it's from "low dissolved oxygen concentration," possibly caused by an algae bloom and warmer water temperatures in the upper end of Lake Houston.
The fish mostly affected are the Gizzard Shad and catfish.
Kish is glad to see the fish kill is dissipating, and hopes she goes at least another 18 years with out seeing it again.
"I've not seen this before and it's always troubling when you see dead wildlife," she said.
The city of Houston has been checking Lake Houston, and tell us there is no impact on drinking water.