We've been lumbered with the goldfish. I knew we would be. Senior Son brought it home from university at the end of last term, along with all his dirty washing and a car full of lager cans and takeaway wrappers. And, to be fair, some generous and thoughtful Christmas presents. He made one token gesture at clearing out poor Timo's bowl (it involved a mixing bowl, a colander and a lot of mess, none of which he cleared up) and then he left the poor creature on the shelf in his room.

Over the next three weeks his room, so clean and sparkling when he came home, gradually grew to resemble a scene from one of those distressing documentaries about deprivation.

The dirty clothes piled higher, the floor vanished under discarded newspapers and sweet wrappers, dirty mugs and glasses gradually filled up the window sill and the poor fish disappeared into the gathering

gloom.

Then Senior Son was ready to go back to his studies. The car was loaded up. He had his bags full of clean washing, a box of groceries and a food parcel of cake and corned beef pie. But something was missing.

We stood on the doorstep, making our fond farewells.

"What about the goldfish?" I said. "Surely you're taking that back with you?"

"Oh, yeah, alright." said Senior Son coming back into the house to get it.

"No," said his father, blocking the way. "I cannot let any living creature, not even a goldfish back into your care."

So Senior Son went and all we are left with is the lingering smell of trainers and responsibility for a goldfish.

Not that we could see it, at first.

To be honest, the bowl and water were so filthy, it was difficult tell if it was still there. Even the fluorescent pink skull, so vivid, so repulsive, had dulled down to a dirty brown while the fish was under Senior Son's negligent care.

Smaller Son was far more sympathetic. He transferred Timo to a plastic pot that once held Tesco's spinach soup and carried out a major spring clean of the poor fish's bowl. He rinsed the gravel, even scrubbed the pink skull. At the top of a cupboard we found the old fish bowl we'd had years ago, bigger than the one Timo was used to, even some plastic plants which I'd carefully saved. We polished them up as a tank-warming present. And finally we transferred the poor fish to his new, large, sparkly clear home.

He'd never had so much attention. At first he just lay there, probably dazzled by the daylight, which he just wasn't used to. Then he whizzed round and round, through the skull's eye sockets a few times and seemed excited and happy. So THAT'S what the world looks like.

Meanwhile Senior Son rang from Manchester. He'd moved flats, he said. Still in the same hall of residence, but the girl in the flat with some of his mates had got fed up with the squalor in which they lived, so had asked Senior Son to swop with her.

"It's a bit untidy," said Senior Son, "but I don't mind that."

A bit untidy? By anyone else's standards that probably means a threat to the public health and a case for decontamination.

That goldfish does not know how lucky it is