OK so what is it? The fartet is a tiny fish only found in Spain and North Africa and is an officially listed species in danger of extinction.
This tiny fish, which is less than two inches long when fully grown needs the purest seawater to survive. They also love the banks of posidonia grass, which also only grows in the cleanest of water. As signs of clean water nothing beats the little fish and the underwater grass.
The fartet has little silvery/blue stripes along its body, a striped fan tail, big eyes and fins top and bottom. It loves eating marine insects and mosquito eggs and likes hot salty water, particularly around traditional salt pans.
If you visit the Mar Menor look out for them.