Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus) male watching over brood of eggs. Female dies after egg laying while male dies once the eggs have hatched. Hokkaido, Japan. May.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus) juvenile aged one year. Photographed on release into wild, raised at research facility. Hokkaido, Japan. May.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus) juvenile aged one year. Photographed on release into wild, raised at research facility. Hokkaido, Japan. May.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus) juvenile aged one year. Photographed on release into wild, raised at research facility. Hokkaido, Japan. May.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus) juvenile on marine algae. Hokkaido, Japan. May.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus) embryos inside eggs, eyes visible. Non-viable eggs without embryos presernt. Hokkaido, Japan. May.

Tony Wu / Dwarf lumpsucker (Eumicrotremus awae) Miyagi Prefecture, Japan.

SCOTLAND: The Big Picture / Lumpsucker (Cyclopterus lumpus) juvenile on a kelp frond, Sula Sgeir, Western Isles, Scotland, UK, February.

Alex Mustard / Detail of the egg mass of a lumpsucker (Cyclopterus lumpus). Babbacombe, Torbay, Devon, UK. English Channel, North East Atlantic Ocean.

Tony Wu / Lumpsucker (Eumicrotremus uenoi) juvenile sitting on algae (Colpomenia sinuosa). Sea of Japan, Japan. March.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus), juvenile resting on algae (Colpomenia sinuosa). Toyama Prefecture, Honshu, Japan. March.

Tony Wu / Smooth lumpsucker (Aptocyclus ventricosus), juvenile with mouth open sitting on algae. Toyama Prefecture, Honshu, Japan. March.

Terry Whittaker / Arctic fox (Vulpes lagopus) blue colour morph female with lumpsucker fish (Cyclopterus lumpus) scavenged from the beach. Hornstrandir Nature Reserve, Iceland. March

Terry Whittaker / Lumpsucker fish (Cyclopterus lumpus) drying in sun, traditional method of drying fish, Flatey Island, Breioafjorour, Iceland. July

Terry Whittaker / Lumpsucker fish (Cyclopterus lumpus) drying in sun, traditional method of drying fish, Flatey Island, Breioafjorour, Iceland. July

Franco Banfi / Lumpsucker (Cyclopterus lumpus) yellow egg mass, Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Franco Banfi / Lumpsucker (Cyclopterus lumpus) male animal, Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Franco Banfi / Lumpsucker (Cyclopterus lumpus) male animal guarding his yellow egg mass, Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Franco Banfi / Lumpsucker (Cyclopterus lumpus) male animal, Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Franco Banfi / Lumpsucker (Cyclopterus lumpus) male, Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Alex Mustard / A male Lumpsucker (Cyclopterus lumpus) guarding his yellow egg mass. Gulen, Bergen, Norway. North East Atlantic Ocean.

Alex Mustard / Female Lumpsuckers (Cyclopterus lumpus), already striped of their valuable eggs, which is sometimes known as Danish caviar, packed in ice at a fish processing plant. Husavik, Iceland.

Alex Mustard / A female Lumpsucker (Cyclopterus lumpus) caught in a net. There is an active fishery for lumpsuckers in Iceland, as the eggs of the female are sold as caviar. Female lumpsuckers only visit shallow wat...

Alex Mustard / A male Lumpsucker (Cyclopterus lumpus) uses his sucker (modified pelvic fins) to attach to this rock in the surge of water moving through this kelp forest. Hallbjarnarstadur near Husavik, north east I...

Alex Mustard / A portrait of a colourful male Lumpsucker (Cyclopterus lumpus). Gardur, south west Iceland, North Atlantic Ocean.

Alex Mustard / 2020VISION / Lumpsucker (Cyclopterus lumpus) male in shallow water guarding eggs beneath Swanage Pier, Dorset, England, UK, English Channel, May

Alex Mustard / 2020VISION / Lumpsucker (Cyclopterus lumpus) colourful male guarding a clutch of eggs, St Abbs reserve, Berwickshire, Scotland, UK, North Sea, April

Alex Mustard / 2020VISION / Juvenile Lumpsucker (Cyclopterus lumpus) attached to a kelp frond with its pelvic fins, which are modified into a sucker. Shetland Islands, Scotland, UK, June

Scott Leslie / Lumpfish (Cyclopterus lumpus) portrait, Nova Scotia, Canada

Scott Leslie / Lumpfish (Cyclopterus lumpus) portrait, Nova Scotia, Canada

Ingo Arndt / Lumpfish (Cyclopterus lumpus) twenty seven centimeters long, Helgoland, Germany

Ingo Arndt / Lumpfish (Cyclopterus lumpus) twenty seven centimeters long, Helgoland, Germany

Tony Wu / Juvenile lumpfish (Eumicrotremus taranetzi), about 3mm in size, sitting on Blue bat seastar (Patiria pectinifera). Pacific Ocean, Hokkaido, Japan.

Tony Wu / Okhotsk atka mackerel (Pleurogrammus azonus) about to swallow swimming lumpfish (Eumicrotremus taranetzi), which was regurgitated moments later. Pacific Ocean, Hokkaido, Japan.

Tony Wu / Mature lumpfish (Eumicrotremus taranetzi) with visible disk comprising modified pelvic fins used as sucker to adhere to rocks and other surfaces. Pacific Ocean, Hokkaido, Japan.

Tony Wu / Mature lumpfish (Eumicrotremus taranetzi) with ability to control each eye independently. Pacific Ocean, Hokkaido, Japan.

Tony Wu / Mature lumpfish (Eumicrotremus taranetzi) wrapping caudal fin around body while swimming. Pacific Ocean, Hokkaido, Japan.

Franco Banfi / Male Lumpsucker (Cyclopterus lumpus), portrait, Vevang, Norway, Atlantic Ocean.

Franco Banfi / Male Lumpsucker (Cyclopterus lumpus) guarding his yellow egg mass, Trondheimfjord, Norway, North Atlantic Ocean.

Franco Banfi / Scuba diver observing male Lumpsucker (Cyclopterus lumpus) guarding his yellow egg mass, Trondheimfjord, Norway, North Atlantic Ocean. Model released.

Franco Banfi / Male Lumpsucker (Cyclopterus lumpus) guarding his yellow egg mass, Trondheimfjord, Norway, North Atlantic Ocean.

Franco Banfi / Male Lumpsucker (Cyclopterus lumpus) guarding his yellow egg mass, Trondheimfjord, Norway, North Atlantic Ocean.

Shane Gross / Pacific spiny lumpsucker (Eumicrotremus orbis) underside showing the fused ventral fins that form a suction disk, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Shane Gross / Pacific spiny lumpsucker (Eumicrotremus orbis) portrait, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Shane Gross / Portrait of a Pacific spiny lumpsucker (Eumicrotremus orbis) suctioned to a kelp frond, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Shane Gross / Pacific spiny lumpsucker (Eumicrotremus orbis) yawning while resting on kelp frond, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Shane Gross / Pacific spiny lumpsucker (Eumicrotremus orbis) underside showing the fused ventral fins that form a suction disk, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Tony Wu / Juvenile Smooth lumpsucker (Aptocyclus ventricosus) momentarily meeting a shrimp on a blade of Eelgrass (Zostera marina), Hokkaido, Japan, Pacific Ocean.

Alex Mustard / A tiny, juvenile Lumpsucker (Cyclopterus lumpus) attached to a Kelp (Laminaria hyperborea) blade, Loch Carron, Highlands, Scotland, UK.

Alex Mustard / Male Lumpsucker (Cyclopterus lumpus) swimming through Kelp forest (Laminaria hyperborea), Loch Carron, Highlands, Scotland, UK.

Alex Mustard / Male Lumpsucker (Cyclopterus lumpus) swimming through Kelp forest (Laminaria hyperborea), Loch Carron, Highlands, Scotland, UK.

Alex Mustard / Juvenile Lumpsucker (Cyclopterus lumpus) sheltering in sugar kelp (Laminaria saccharina). Kinlochbervie, Sutherland, The Highlands, Scotland, United Kingdom. Loch Inchard, The Minch, North East Atlant...

Alex Mustard / Distinctively grey coloured female Lumpsucker (Cyclopterus lumpus) attached to a kelp frond with her sucker (modified pelvic fins) The females of this species are rarely seen in shallow water. Kinloch...

Alex Mustard / Bright orange male Lumpsucker (Cyclopterus lumpus) in shallow water in springguarding eggs. Photographed in May under Swanage Pier. Swanage, Dorset, England, British Isles. English Channel.

Tony Wu / Newly hatched Lumpsucker (Eumicrotremus awae), 2mm to 3mm in size. The fish is perched on a species of red algae, possibly Polypes sp. Kanagawa Prefecture, Honshu, Japan.

Tony Wu / Lumpsucker (Eumicrotremus awae) newly hatched. The fish is 2mm to 3mm in size, perched on brown algae (Lessoniaceae). The white ring pattern is characteristic of juveniles, disappearing as the juvenil...

Shane Gross / Portrait of a Pacific spiny lumpsucker (Eumicrotremus orbis) fish at night off Vancouver Island, British Columbia, Canada.

Shane Gross / Portrait of a Pacific spiny lumpsucker (Eumicrotremus orbis) fish at night off Vancouver Island, British Columbia, Canada.

Shane Gross / Lumpfish (Cyclopterus lumpus) sheltering in Eelgrass (Zostera marina) bed. Lumpfish are hunted for their roe to produce caviar and are considered threatened in Canada. Terra Nova National Park, Newfou...

David Hall / Pacific spiny lumpsucker (Eumicrotremus orbis), yellow form, which has fused ventral fins that form a suction disk, enabling it to attach itself to rocks and seaweed, Gambier Bay, Alaska, USA. August.

David Hall / Pacific spiny lumpsucker (Eumicrotremus orbis), red form, which has fused ventral fins that form a suction disk, enabling it to attach itself to rocks and seaweed, Gambier Bay, Alaska, USA. August.