The CeNak hosts the largest fish collection of Germany. The 260,000 cataloged specimens in this collection represent more than 8,000 fish species, which are about 25 % of all known fishes worldwide. The collection contains more than 1,300 type series from which about 42 % are primary types.
Valuable historical objects from former collections of Godeffroy and Bleeker also belong to the fish collection of the CeNak. The oldest specimens in the fish collection originate from 1838.
The fish collection is world-wide in coverage. Extensive and often used material of freshwater fishes stems from Europe, Asia and Africa as well as from South and Middle America. Marine fishes are mainly represented by lots from the Atlantic Ocean and adjacent waters, especially from the North and Baltic Seas. The collection comprises about two-thirds of all fish species known to occur in the Atlantic Ocean and holds also comprehensive material from the Pacific and Indian Oceans.
Elasmobranchii, the second largest group in the fish collection, is represented with more than 2,650 lots. Approximately 7 % of the species represented in the fish collection are elasmobranchs. 93 % are actinopterygians, the largest group of fishes occurring in the fish collection.
Elasmobranchii are mainly represented in the collection with the family Rajidae (more than 1,400 lots) whereas the family Myctophidae is a group of Actinopterygii with the highest number of catalogued lots (more than 4,800) in the collection.
Numerous species in the collection are represented by several of their life history stages: eggs, larvae, juveniles, adults. A majority of the fish specimens is stored in a liquid preservative (mainly 70% ethanol) and maintained in glass jars or stainless steel tanks. The collection also contains some specimen fractions such as skin preparations, dried skeletons, skulls, jaws, scales and otoliths, as well as DNA samples, photographs, x-rays and related publications.
The majority of the holdings of the fish collection is digitalized.