Jared, wow, that stock looks great! I've never made stock with fish; just chicken, turkey, and ham bones.
I've only used cider vinegar as the acid too; never thought to use something else. Plus, since my recipe only calls for 1 tablespoon, I assumed it didn't make much difference. It's just to help pull minerals out of the bones, I thought.
It sure makes a GREAT base for soup, though!
Glad you think it looks good. It actually tastes delicious! If you like making stock, I would try this recipe.