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The Établissement public du Palais de la Porte Dorée is responsible for developing the scientific and cultural projects of the Aquarium tropical and the Musée national de l'histoire de l'immigration (National Museum of the History of Immigration) and for promoting the heritage of the Palais de la Porte Dorée.
Tomato clownfish
On encountering certain tropical sea anemones, clownfish can frequently be observed alongside them, living as a group or a pair according to species. This behaviour may seem surprising since the tentacles of sea anemones contain stinging cells that can sting, paralyse and kill fish of the same size who will then be absorbed into the anemone. Clownfish, on the other hand, seem to be immunised against stings; they will even enter the anemone to protect themselves from predators, and lay their eggs close by. The mucus coat of the anemone contains a "time-release substance" that inhibits activation of the stinging cells when the tentacles touch each other. Clownfish immunise themselves by rubbing against the anemone, very briefly to start with, to gradually coat themselves with this substance which will protect them later. The association of the clownfish and the anemone is a form of symbiosis since it is mutually beneficial. Each clownfish has its own assigned anemone which it provides with food in the aquarium. In the ocean, the clownfish defends its anemone against attacks from butterflyfish, which may graze on its tentacles. Clownfish are protandrous hermaphrodites. Within a group of clownfish, the biggest one will be a female, the others are males. When the female dies, the biggest male turns into a female. The female is much bigger than the male. When it is young, it sports 3 white stripes for a few weeks. Gradually, the tail stripe disappears, then the one on the middle of the body. By the age of 3 to 4 months, only the stripe on the back of the head remains. A black spot also develops in the middle of the body and its colour intensifies in the adult fish.
Banded archerfish or toxote
This fish lives in the mangroves and in brackish water habitats throughout Asia. The archerfish spits strong, accurate jets of water from its mouth at insects and gastropods living in the vegetation above the water, to a distance of over one metre. It keeps water under pressure in its mouth, pointing it upwards. When the archerfish shoots, the gill covers contract suddenly, compressing the water in the mouth and gill cavities. The jet is guided by a groove created in the roof of the fish’s mouth. From the water, the archerfish aims at land-based prey. To reduce light refraction through the water surface, the archerfish comes as close as it can to being directly beneath its prey. Young archerfish are less accurate in their shooting: they may work together and use group fire to bring prey down into the water. Lastly, if the prey remains in place despite the shooting, the archerfish can jump out of the water to grab it, to a height of 30 cm.
Banggai cardinalfish
Également appelé poisson-cardinal, il illustre parfaitement ce qu’est une espèce endémique . En effet, son aire de répartition est limitée aux Îles Banggaï situées au nord-est de Sulawesi (Célèbes) en Indonésie. Parallèlement, cette espèce illustre aussi les relations mutualistes formées avec un autre animal. Les jeunes, après avoir été recrachés par le mâle qui a incubé les œufs puis les larves dans sa bouche pendant une quinzaine de jours, se réfugient entre les épines des oursins diadèmes ( Diadema setosum ) lorsqu’un danger se présente. Ensuite, ils se protégeront entre les tentacules des anémones et cohabiteront éventuellement avec de jeunes poissons-clowns. Les adultes restent volontiers à proximité des oursins diadème. L’Apogon de Kaudern est inscrit sur la liste rouge de l' UICN . Face à cette situation, les aquariums publics ont entrepris avec succès la reproduction de cette espèce. Tous les individus présentés à l’Aquarium tropical sont issus d'une reproduction ayant eu lieu en Aquarium. Cette démarche illustre la mission de conservation des aquariums publics, qui participe au maintien de la biodiversité aquatique. L'espèce a cependant été réintroduite avec succès dans le détroit de Lembeh, ainsi qu'au Nord de Bali où elle prolifère facilement. Le mâle récupère les œufs dans la bouche et y conserve les alevins jusqu'à une taille d'environ 8 mm. Ils ressemblent alors à des adultes miniatures.
Pig-nosed turtle
The only representative of its genus, its characteristics are unmistakable. This is the only turtle with a prominent snout that gives it its name. Its carapace, covered with a thin skin, is a uniform grey to dark brown on the upper part with a cream-coloured plastron. Its feet are flippers like marine turtles, better adapted to swimming. It is exclusively aquatic, living in rivers but able to make a few incursions into the ocean. Its omnivore diet consists in fish, crustaceans, snails and fruit. Its snout is adapted to searching for prey in the mud. During the dry season, the females lay their eggs in the upper part of river banks or beaches, after digging a nest. Only when the water level goes up again at the end of the dry season will the eggs hatch when the nest becomes covered with water. This species has become endangered due to the quality of its flesh, appreciated by local populations in Papua. The eggs are also widely consumed, and destroyed by the herds of buffalo that trample the river banks where the nests are located. Breeding programmes are underway, notably in Australia, but unfortunately the results have been fairly limited so far.