The color of the roux depends on your taste and what it is being used in. Gumbo I don't use dark but a light tan. For shrimp or crawfish étouffée in South Louisiana a dark roux is used. Yours looks a little to dark.
The best roux is still made the old fashion way with lard. You don't eat enough of it to be a health problem.
If you look at the store bought jars of roux some are pretty dark.
Cook about 45min. for peanut-butter and 55 min for dark mahogany color. If you see any black specs START OVER you just burned it.
Happy rouxing
A dark roux
A light roux or white