I was taking a break from not seeing the birds I was looking for on the edge of Cardiff Bay yesterday, when a loud splash drew my eye down to the water. These fish, a shoal of at least ten, perhaps more, were swirling and weaving around each other, presumably feeding.

Officially known as Thick-lipped mullet (Chelon labrosus), they are also frequently called Thick-lipped grey mullet, Thicklip mullet, Grey mullet and various other combinations of those words.

I wasn’t able to judge their size accurately, but it seems they can grow up to 75cm in length, though they mature when around 30cm at between four and six years of age. They thrive in ‘low salinity environments’ like Cardiff Bay and are often ‘found in closely shoaling schools near the surface’, just like those I saw.

They feed ‘on organic and algal material found on the upper surface sediments and mud, with the indigestible material being filtered out by the gill rakers’. I’m not sure I’d want to put any sediments or mud from Cardiff Bay in my mouth, so their filtration system must be first rate to survive the pollution.

I have to admit that they were very calming to watch, and I gained some appreciation for why people have aquariums, though I do prefer creatures to be wild and free.
Credit: Today’s fishy facts came from the UK Fish info website.