I think it may be true. There is a giant catfish that really has the ability to kill people. During the breeding season, they will nest underwater, but catfish have the behavior of protecting their nests. People go into the water and disturb the catfish, so the catfish attacks people. This is my understanding.

But there is also a possibility because catfish is omnivorous. It is also possible that people drowned and catfish ate people to death. This is not impossible.

If you have time, you can watch The River Monster, in which the aggressiveness and strength of giant catfish are described in detail. And introduced some other killer fish.