There are some strong indicators that the Arkansas River Valley, from Hot Springs West, to about Norman, Oklahoma, may be smack dab over an unmapped caldera.
Importantly, drum fish are bottom feeders, so would be particularly sensitive to toxic gases percolating up from fumeroles through the river bottom, that would be dispersed higher up by the running water. The most toxic of these gases include Hydrogen Fluoride, Hydrogen Sulfide, Hydrochloric Acid, and Sulfuric Acid.
Now I'm hoping it was *just* a Muslim Sarin test.
Your theory makes a helluva lot more sense than the usual
tripe about Muslims poisoning us.