I suspect the fish pond pump might be leaking power into the water. The fish is certainly happier when I don't run the fountain. I don't know if "happier" is the right word to apply to a fish; "not distressed" might be better. When the pump isn't running, the fish isn't trying to leap out of the water.
"Webforge" sounds like an online HTML mill that churns out web sites in bulk. They do, in fact, make galvanized grates.
I have a new ray gun. Photos to come.