The ichthyology section houses collections of fishes from all over the world. The Indian Ocean, and above all the Arabian Seas Region (Red Sea, Gulf of Aden, Arabian Sea, Gulf of Oman and The Gulf) are the geographic focus of marine fish collections, while freshwater fish collections are predominantly from the Middle East and Eastern Africa. About 55,600 series with an estimated more than 150,000 specimens are presently in the holdings of the fish section. Large parts of the collection have been entered into an electronic database.
The historical collections and 1820 type specimens are of particular importance. The collections include 305 holotypes, 802 paratypes, 346 syntypes, 98 lectotypes, 222 paralectotypes, and 29 unspecified types. A type catalogue is currently being compiled.