I didn't want to add a writeup here (in fact, I sent a /msg to ba about this, as soon as I read his), but:
You can drown a fish in oil. Olive oil, corn oil, 10W30, what have you. In fact, you can drown a fish in any oxygen-poor liquid, including water itself!
But please, don't try this at home, it's cruelty to animals!
There is, of course, a more figurative meaning to this: "Can you drown a fish ... in tartar sauce?" YES! You might really like tartar sauce a lot, but don't overdo it! If you're a fan of salt or hot sauce, take care not to drown your fish (or any other food, for that matter) in those condiments either.