Heat is being blamed for a large die-off of fish in Lake Arlington. 200 to 300 hundred fish died after the Excelon Power Plant discharged warm water into the lake. That’s a common practice, but Melissa Dudley from Texas Parks and Wildlife says in extreme heat, water becomes deprived of oxygen.  This is what kills the fish. The temperature at the plant’s discharge site yesterday was 99 degrees. The Fort Worth Parks Department are removing the fish as they wash up on shore.