When I was at university, I shared a flat with my best friend from school. The first thing we bought together, after porridge and lentils, was a goldfish. He was bright orange; cost £2.50 from the local pet shop and we called him Azzedine.

I'd never kept fish before and they surprised me. They didn't bubble, their poo trailed behind in a long finger as they swum, and they had a better memory than the three seconds people supposed. We got into the habit of buying other goldfish. Myrtle was next and then Pig, so called because he was both beautiful and ugly with a captivating, inbred look. These effervescent and colorful little creatures were the currency of our friendship. But until Pig died, aged six months or so, I'd never considered what to do with a dead goldfish.

We had discovered Pig dead, belly to the air and floating next to a large fly. It was a macabre encounter, particularly with the other two fish lingering at the bottom of the tank in stale water. My flat mate didn't hesitate: she picked Pig up with paper towel and flushed him down the loo. A bright orange point in the city's waste, he got buried in pee and bleach.

Long after we'd stopped living together, Azzedine died. He floated in the middle of the tank, long tail touching the bottom. The first time I held him was when I picked him dead out of the water. He was so light and cold and wet: sensations that showed the obvious, that goldfish are pets you watch rather than touch. It seemed like a sad and hopeless thing, to flush him down the loo. I remembered staring down the porcelain toilet bowl at Myrtle when she'd died: a tiny, colourful friend put in the place of waste. Instead, I laid Azzedine out in a long matchbox and put him in the freezer.

No one knew he was there until my brother asked about the plastic package at the back of the meat drawer. By then, he'd been on ice for over a year, and after that the truth soon trickled out. Friends, family and colleagues started finding out about the goldfish in the freezer. Frozen is an undecided state, neither rotten nor fresh, and undecided was just how I felt. I kept pretending to be trying to find the time for a burial, to be planning to dig up a patch of ground next weekend. But next weekend never came. Secretly, I hadn't confronted the question, how to dispose of Azzedine?

The freezer decided for me: it needed defrosting. The fish fingers were inaccessible and the broccoli florets were caged in by furry ice. Now with a dripping freezer and packets of wet warm peas to worry about, there seemed only one good place for Azzedine and that was back to the water. So I took him to the Thames, tied a stone around his matchbox and dropped it in. The parcel floated away and sunk into the river. Azzedine was defrosting two years late.

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