Lumpsuckers range in size from two centimetres up to 50 centimetres
Two lumpsucker fish, a male and a female, have been caught in the North Sea by a fisherman in Blyth.
Unsure of what they were, the fisherman took them into the Blue Reef Aquarium in Tynemouth.
The two fish are already showing signs of breeding and it is hoped that they will eventually start producing eggs of their own.
They are now being looked after at the aquarium and are on show for people to see up close.
'Least graceful fish'
The eggs are commonly eaten as caviar.
Lumpsuckers are scaleless, flabby fish named for the large sucking disc on their underside.
They feed on a variety of animals including crustaceans, small fish, worms, fish eggs and comb jellies.
The fish can look quite unusual because their pelvic fins are adapted to form a powerful sucker on their undersides which become useful for clinging to rocks, allowing the male to stay anchored to the rocks beside his eggs.
Lumpsuckers breeding occurs from January to May when they move inshore and spawn, usually amongst kelp and the male protects the clump of up to 200,000 eggs from predators until they hatch.
Blue Reef's Zahra d'Aronville said: "Lumpsuckers get their name from specially adapted pelvic fins on their bellies which form a suction cup.
"They've been described as one of the marine world's least graceful fish and they certainly look strange with their scaleless blue-green skin and deep bodies covered with bony lumps."