Lookdown fish

The Lookdown fish, also known as Selene vomer, is a species of marine fish that is found primarily in the western Atlantic Ocean. Known for its distinct body shape, this fish is a unique addition to any marine aquarium. In this article we will discuss the natural habitat, diet, and care requirements of the Lookdown fish, and provide tips for keeping this species in an aquarium at home. Whether you are an experienced aquarist or a beginner, this article will provide you with the information you need to successfully keep and care for the Lookdown fish.


The Lookdown fish has a distinct, slightly curved body shape and a unique “hump” on its forehead. They have a silver coloration and a sleek, streamlined appearance. They have a dorsal fin that runs the length of the back, and a forked tail fin. They have large eyes that are set high on the head, which gives them a unique, upward-facing gaze. They also have a small mouth with sharp teeth. They are called lookdown fish because of their apparent looking down design. They have camouflaging capabilities as they can manipulate the pigmentation into a mirror-like body that reflects high light or dim light, depending on the situation and what best camouflages them in that moment.

Natural environment & behaviour

They are usually found in coastal waters and can be found near the surface of the water, in bays, lagoons, and estuaries. They are typically found in schools, and they are considered to be a pelagic fish, meaning that they spend most of their lives swimming in the open waters of the ocean rather than near the bottom. They are also known to prefer clear water and a sandy bottom. They can be found in high salt as well as brackish water with wide temperature ranges. They are escape artists when chased by predators, not just because of their camouflage skills but also because of their body shape, making them agile and surprisingly quick.


The Lookdown fish is carnivorous and its diet should include a variety of meats such as brine shrimp, squid, krill, mysis shrimp, and small fish. They may also accept flakes or pellets formulated for carnivorous fish. They are known to be picky eaters, so it may take some time to find the right food that they will accept. It’s important to feed them small, frequent meals throughout the day, rather than one large feeding. This will help to maintain the water quality and prevent overfeeding, which can lead to health issues. It’s also important to vary their diet as much as possible to provide a balanced nutrition and to avoid boredom. Also to note that since they are schooling fish, they should be fed as a group and not individually. This helps to promote natural feeding behavior and reduce competition among tankmates.

Keeping a lookdown fish

When provided with open swimming spaces in a large tank, this species is very hardy and can live a long time. As they are a shoaling fish, it is preferable to keep them in groups of 4 or more. They are a peaceful fish but nonetheless do not keep them with too small of fish as they can eat them. Batfish for example are good companions, as these fish are large and need the same open big swimming spaces. They are also tolerant of a wide range of salinity, temperature and not so optimal water conditions. Yet for long term success provide them with as clean as possible aquarium water.

The best temperature to keep a Lookdown fish in an aquarium is between 24 – 27°C (75 – 80 °F). This range of temperature mimics the natural habitat of this fish, which is found in the warm waters of the western Atlantic ocean.

It’s important to maintain a stable temperature in the aquarium, as sudden temperature changes can be stressful for the fish and can lead to health issues. A good aquarium thermometer and a heater can help you to maintain the appropriate temperature range for your Lookdown fish. Also, keep in mind that the temperature should be consistent throughout the tank, as Lookdown fish can be sensitive to temperature gradients. This can be achieved by using multiple heaters and placing them in different areas of the tank.

Scientific nameSelene vomer
Type of aquariumMarine
SizeUp to 50 cm / 19.7 inches
Weight2 kg
RegionThe Caribbean Sea and the Gulf of Mexico
Ideal tank size380 liters / 100 gallons
Ideal water temperature24 – 27 °C / 75 – 80 °F
Ideal specific gravity1.020 – 1.025
pH7.5 – 8.5
DietBrine shrimp, squid, krill, mysis shrimp, small fish, flakes or pellets


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