A cure for blindness by reversing damage to the retina could be on the horizon - thanks to the zebrafish, according to new research.
Scientists have identified a brain chemical that could hold the key to how the fish regrows damaged retinas, the light sensing tissue at the back of the eye.
Its levels drop when the unique self repair process kicks in - so blocking it could lead to new treatments for AMD (age related macular degeneration), the most common cause of blindness.
There are two forms, dry and wet, and they affect at least half a million people in the UK to some extent. It causes damage to the macula, a small spot near the centre of the retina needed for sharp, central vision.
In the UK 44,000 people a year develop dry AMD. The dry form of AMD affects 85 per cent of patients and causes gradual loss of central vision, but does not affect peripheral vision. The Macular Society estimates 44,000 people a year in the UK develop dry AMD.
Fish and mammals retinas are basically the same - and their rebirth is started by a reduction in GABA (gamma aminobutyric acid) a neurotransmitter vital for sight.
The retina contains a special type of adult stem cell, called Müller glia which in fish play a key role in regeneration.
When regeneration is triggered in zebrafish, the Müller glia begin proliferating and then differentiate into replacements for the damaged nerve cells.
Müller glia cells are also present in the retinas of humans and other mammals, but don't regenerate.
Zebrafish are easily blinded but due to their robust regenerative ability their eyes recover in just 28 days.
It could also treat a rarer condition called retinitis pigmentosa. The inherited disorder affects 3,000 Britons and causes gradual deterioration of the retina, which can also leading to loss of sight.