too much anchovy
I'm assuming you're using canned anchovy filets packed in oil. Or are you using salt packed anchovies? Or maybe some other form?
Try soaking your anchovy filet in milk for 5 minutes or so before use. That will draw out some of the salt and strong flavor.
Depending on the application, I substitute Vietnamese fish sauce for anchovy filets. Assuming you're sparing in its use, it does not taste fishy, but adds umami and a subtle saltiness to whatever you're cooking. A stew would be a great application for Viet or Thai fish sauce.