I could be wrong, but I don't think Eucha is known as a catfish lake, of course I'm sure there are some in it, I've seen some good flatheads in Spavinaw Creek below Spavinaw Lake, and used to get some in my noodlin barrels at the mouth of spavinaw where it feeds Hudson.
I'd fish the navigation channel, or grand river. Just my 2 cents worth.