Ten nudibranch species in exact licensed photographs. The video compares colour, rhinophores, gills and body shape; it is an editorial selection, not a field guide. Photograph credits: 1. Glaucus atlanticus 1 cropped.jpg; Taro Taylor from Sydney, Australia; CC BY 2.0; ; https://commons.wikimedia.org/wiki/File:Glaucus_atlanticus_1_cropped.jpg; 2. Babosa de mar (Chromodoris lochi), Anilao, Filipinas, 2023-08-21, DD 102.jpg; Diego Delso; CC BY-SA 4.0; ; https://commons.wikimedia.org/wiki/File:Babosa_de_mar_(Chromodoris_lochi),_Anilao,_Filipinas,_2023-08-21,_DD_102.jpg; 3. Hypselodoris bullockii, pareja.jpg; Steve Childs; CC BY 2.0; ; https://commons.wikimedia.org/wiki/File:Hypselodoris_bullockii,_pareja.jpg; 4. Nembrotha kubaryana.jpg; Nhobgood; CC BY-SA 3.0; ; https://commons.wikimedia.org/wiki/File:Nembrotha_kubaryana.jpg; 5. Babosa de mar (Phyllidia varicosa), Anilao, Filipinas, 2023-08-21, DD 122.jpg; Diego Delso; CC BY-SA 4.0; ; https://commons.wikimedia.org/wiki/File:Babosa_de_mar_(Phyllidia_varicosa),_Anilao,_Filipinas,_2023-08-21,_DD_122.jpg; 6. Flabellina affinis 2.jpg; Heike Wägele & Annette Klussmann-Kolb; CC BY 2.0; ; https://commons.wikimedia.org/wiki/File:Flabellina_affinis_2.jpg; 7. Cadlina luteomarginata, Monterey.jpg; Ed Bierman; CC BY 2.0; ; https://commons.wikimedia.org/wiki/File:Cadlina_luteomarginata,_Monterey.jpg; 8. Antiopella Cristata.jpg; Roberto Strafella; CC BY-SA 4.0; ; https://commons.wikimedia.org/wiki/File:Antiopella_Cristata.jpg; 9. Pikachu Nudibranch Thecacera pacifica 1.jpg; Olakhalaf; CC BY-SA 4.0; ; https://commons.wikimedia.org/wiki/File:Pikachu_Nudibranch_Thecacera_pacifica_1.jpg; 10. Jorunna parva, Osezaki.jpg; Izuzuki Diver; CC BY-SA 2.5; ; https://commons.wikimedia.org/wiki/File:Jorunna_parva,_Osezaki.jpg;