... is a strong, overbearing taste, it could be the red meat that's causing it. Many members have stated that, if you filet off the reddish meat portion of your Catfish fillets, the strong (muddy ?) taste will be lessened or removed.
I can't personally verify this, as I've seldom kept Catfish to eat. And the ones I did keep/eat ... were before I had heard of this.

It is, however, a good practice to remove & disgard any of the yellow fat along with the entrails, eggs, & skin. These are where most of the pollutants will congregate within the fish ...

... cp