Wrong.
Both the fish and the electricity need to be considered in a long term utilitarian framework.
The only reason you seem to have two conflicting objective truths is because your time window is too short.
Says who?
You have an infinite regress problem here. You eventually are going to have to fall back on non objective feelings about how the world should be to justify your actions.
Depending on how you define "utility" - this is either a meaningless tautology that doesn't say anything at all, or a subjective belief that can be easily challenged by equally subjective alternatives.