I brought the milk to the boil, then put a lid on and set it to simmer while I pottered around getting some veges ready. About halfway through the cooking time, I decided I ought to turn the fish over, since the top was not covered by the milk. I wasn't sure it would heat through.
I was dismayed to discover, when I turned the fish over, that it still had scales attached. Well, mostly attached: some had come loose and were floating around in the milk. I hadn't had any reason to look at the bottom of the fish when I opened the packet. After all, when does supermarket fish ever have scales on it? They were hidden underneath, like when you get a pack of steak with a good one on top and a gristly one on the bottom. Though if I'm really honest, I hadn't looked at what I'd bought at all. It wasn't even a fillet - it still had bones and skin and everything.
I let the fish simmer away in its milk for the rest of the 15-minute cooking time. When this was up, I returned to the kitchen to find the fish sitting in a watery grey liquid ringed with scum; one of the least appealing sights I've seen in a long while.
I took the fish out and inexpertly removed the scales and any bones I could find. I poured what little liquid remained into a jug, and topped it up with fresh milk. I wasn't feeling particularly optimistic at this stage, but I soldiered on with the sauce.
Having scraped the disturbing scummy remnants from the pan, I melted some butter and stirred through flour. after a minute or two, I started gradually adding the milk, whisking to remove limps. The resulting sauce was a definite step up from what had been in the pan a few minutes previously: it actually looked edible, for a start.
I added parsley and a bit of seasoning, then served up the fish and vege, and poured the parsley sauce over. To my surprise, it was quite edible, even tasty, though really quite salty. as I made my way through the portion, I found the salt was quite overpowering. A pity that this wasn't one of the many times I forgot to season my sauce - there was more than enough saltiness in the fish itself.