Cold weather can stress fish and make them more susceptible to disease. In addition, cold temperatures can cause the water to hold less oxygen, which can also stress fish and lead to death.
Environmental pollution can also contribute to fish kills. Chemicals from industrial plants, agricultural runoff, and sewage treatment plants can all harm fish and cause their death.
In the case of the Texas fish kill, it is likely that a combination of these factors led to the death of so many fish. The cold weather stressed the fish, making them more susceptible to disease and pollution. The environmental pollution then caused the fish to die.
The Texas Parks and Wildlife Department is currently investigating the fish kill and working to determine the exact cause. In the meantime, it is important to avoid eating fish from the affected areas.