Yep, I watched it.
A 1971 pseudo environmental warning horror film about a scientist (mad, of course) who combines the invasive species, The Walking Catfish, and mankind to create a killer fishman – himself.
He kidnaps and kills a few people, looks ridiculous and is silly.
That is all this movie has going for it. Watch it if you like, I found it on Netflix (U.S.). Apparently it was also known as Zaat and is available on Youtube.
Here is the Trailer. and look below that for the entire movie (as “Zaat”)
And Here’s the whole movie: