Is located in the Station's basement and hosts - in its 40 tanks of 80,000 litres total capacity - a multicoloured population of interesting Mediterranean invertebrate and vertebrate marine species such as sea anemones and plants, urchins, algae, corals, bivalves, lobsters, octopuses, numerous fish, sea turtles etc. Unique in its layout and natural decoration the only public Aquarium in Greece gives to its visitors the impression that they share the same environment with the hosted species

The building of the Hydrobiological Station of Rhodes was built during the period 1934-36. In 1937, under Italian rule, it operated as the Reale Istituto di Ricerce Biologiche di Rodi, until 1945, when, after the union of the Dodecanesse with Greece, it was renamed "Hellenic Hydrobiological Institute" and operated under the supervision of the Academy of Athens. Today, the Hydrobiological Station of Rhodes operates as a Museum and Aquarium as well as a research centre,and belongs to the National Centre of Marine Research. The aim of the Hydrobiological Station of Rhodesis the preservation and display of embalmed and living creatures of the Mediterranean sea. In the aquarium the visitors (200.000 per year) can admire specimens of anthozoa, molluscs (gasteropods and cephalopods), species of the crab family, echinoderms, and fish of the following families: Dasyatidae, Mullidae, Sparidea, Centrachantidae, Labridae, Scaridae, Siganidae, Mugilidae, Scopaenidae, Triglidae, Balistidae,Monacanthidae, as well as sea turtles. In the Museum are also displayed exhibits such as various kinds of sharks and other fish, sea turtles, toothed whales, (Odontoceti) and
Mediterranean monk seals.Thanks to the research facilities of the Hydrobiological Station of Rhodos and the National Centre of Marine Research, the Station runs research programmes, covering every aspect of oceanogrphy in the area of the Dodecanesse. It thus functions as a model research unit in the Mediterranean.