To demonstrate the level of toxic material in a brand of anti-dandruff shampoo, a Danish television presenter poured diluted shampoo into a fish tank on a 2004 episode of the consumer affairs show she fronted.

Lisbeth Kloester, a television presenter on the Danish public channel DV1, is now on trial for causing unnecessary suffering to animals.

After being subjected to the shampoo, all but one of 12 guppy fish housed in the aquarium died within four days and a veterinary practitioner watching the show decided to press charges. Under Danish law, causing unnecessary suffering to animals is an offence and Kloester could face a fine if convicted.

Kloester has pleaded not guilty and her lawyer Tuge Tried said he expected his client to be acquitted at the trial on Tuesday.

“The allegations are this experiment caused the fish’s fear and suffering…but expert witnesses told the court on May 12 that this was not the case,” he said. “Fish are killed by suffocation in industrial fisheries and we throw live lobsters into boiling water, but we don’t press charges against fisherman or restaurant owners.”