GM fish detects chemicals in water

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A company in Hong Kong has come up with a new, if slightly disturbing, way of identifying oestrogen-like compounds in the water. The modern day equivalent of the canary in a mine comes in the form of a genetically modified fish in a bowl.

Vitargent, a biotechnology company have created a genetically modified Medaka ricefish (Oryzias latipes) which glows green when exposed to oestrogen-like chemicals known as Estrogenic Endocrine Disruptors or EEDs.

Growing environmental concern is growing about the presence of oestrogenic compounds in the water as they are not removed by the standard sewage treatment plants. Effects witnessed in fish include male fish having delayed sperm development and smaller testes, inter-sex fish that that have both male and female reproductive tissue and skewed sex ratios. Whilst some industrial chemicals such as bisphenol A, mimic oestrogen; little is known about how the combination of different oestrogenic compounds work.

To find out, Xueping Chen and colleagues at Vitargent, combined the green fluorescent protein gene from jellyfish and spliced it into the genome of the fish directly next to a gene that detects oestrogen. Chemicals that have oestrogen-like activity cause the 1mm long fish larvae to express the modified gene, making them glow. The higher the concentration of oestrogen, the brighter the glow.

When the team tested the fish at eight sites around Hong Kong, they found that some chemicals, such as the UV filters in sunscreen, which usually show weak or no oestrogenic activity had combined in water to amplify the oestrogenic effect.

The company are also working on a fish that glows different colours depending on the pollutant detected, although Professor William Price Dean of Science at the University of Wollongong in New South Wales, Australia has warned that the approach does not detect a biological response.

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