The kingfish is actually a Spanish mackerel. The main differences between kingfish and wahoo are the appearance of their heads and their coloration. Wahoo have a blue back with white stripes, while kingfish are predominantly silver with dark angled markings. Additionally, their head shapes differ.

Here are some pictures of wahoo fish and kingfish, which clearly illustrate the distinctions between the two:

I hope these visuals help you understand the differences between these two species. If you have any further questions, feel free to ask.