Staff and customers at Wholesale Tropicals in the East End of London have two preferred topics of conversation: how the character of the rapidly gentrifying neighbourhood is changing and, of course, tropical fish. Brimming with subtle charms, gentle humour and poignant observations, and set to the soothing sound of bubbles percolating through an aquarium’s air pump, the short documentary Bubble provides a portrait of the specialist retailer and its many characters, land- and water-dwelling. Juxtaposing human and fish perspectives on their surroundings, and especially the unusual creatures staring at each through the glass, the UK director Eleanor Mortimer finds a compelling subject in this slice of London, building an understated atmosphere from the small joys that compound with each passing minute.