Sea Life London Aquarium has dived into its annual “count and clean” stocktake of its creatures in preparation for the year ahead.

Expert aquarists have plunged into the water with calculators in hand to kick off their count of the attraction’s 6,000 creatures, including a 27-year-old green sea turtle named Boris who measures 1.5 metres (five feet) in length.

The staff will carry out the mammoth task across the month as they plan to tally up hundreds of leafcutter ants, cockroaches, and one of their smallest species, the milk frog – which is only eight centimetres (three inches) long.

The activity allows aquarists to examine the creatures and create strong bonds with them, as well as clean the windows to the wet wonderland.

Sea Life London Aquarium milk frog being measured
The milk frog is one of the aquarium’s smallest species, measuring at just eight centimetres long (PA)

“Diving into our January ‘count and clean’ is one of the most exciting and important events at Sea Life London Aquarium, as it’s a chance to take stock of all our new arrivals over the past year,” said the aquarium’s general manager, Catherine Pritchard.

“Whilst our aquarists have lots of fun trying to count all of the amazing creatures in our collection, we also perform an early spring clean to help us maintain the health and wellbeing of our creatures both now and for future generations to come.”

Sea Life London Aquarium measuring an octopus
The event allows aquarists to get up close and personal to the marine species in their care (PA)

The largest animal in their tanks is the sand tiger shark at three metres (10ft) long while the smallest on their checklist is the coral polyp, at less than one millimetre.

The experts will also survey 298 clownfish and 90 marble jellyfish as they work to spruce up the South Bank attraction for visitors.