Their main tank, which holds 4,500,000 litres (1,200,000 US gal), is the largest in Northern Europe,[1] but the Oceanarium also has several smaller habitat aquariums and an exhibit with seals.

The large elliptical tank in the centre of the museum's old building measures 22 by 33 metres (72 by 108 ft) and holds 4,500,000 litres (1,200,000 US gal) of water.

[1] It is also a "show-room" for displaying large specimens of some of the species which are also seen in the habitat tanks – for example cod, saithe, turbot and sea-bass.

Other large species in the tank are spiny dogfish, skates, and ocean sunfish.

[1] Twelve tanks, varying in size from 4,000 to 16,000 litres (1,100 to 4,200 US gal), present different habitats from the North Sea - from the sandy bottom by the jetties to the muddy seafloor at several hundred metres in the Norwegian Trench between Denmark and Norway.