etymology 

The family consists of the genus Aplodactylus. The name means either "single finger" or "simple finger" (Greek haploos / aploe + daktylos). [Sourced to Fishbase, depending on whether you look at Aplodactylidae or Aplodactylus-punctatus]
Is anybody able to look at Cuvier and Valenciennes, 1832? This is supposed to be the original source of the genus name, and conceivably gives some insight as to where the name was meant to come from. (Primary sources aren't ideal, but a self-contradictory secondary source isn't better.) Presumably there is some defining and identifying property of the fish's fin, which not only gives it the name but would more broadly also be worth mentioning in the article.