Buglossidium luteum (Teleostei, Acanthopterygii, Pleuronectiformes, Soleidae), larva, length 5.5 mm, Helgoland 03.2016. 0:52 min. Many of the marine fishes produce transparent pelagic eggs, often about 1 mm in diameter. This enables observation of developmental processes in living specimen. They hatch as still transparent larvae which often show colourful pattern of chromatophores. This still bilaterally symmetric Buglossidium luteum soon undergoes strong metamorphosis as a flatfish. Video can be used for teaching.