Celebes Rainbowfish (Marosatherina ladigesi): Ultimate Guide

The Celebes Rainbowfish (Marosatherina ladigesi), also known as sail-fin silverside rainbowfish, is a member of the Melanotaeniidae family. They are the smallest species of the rainbow family. The story of the name stems from the geographical area of origin, but also pays respect to the ichthyologist who discovered this specific species, Werner Ladiges. More interestingly, Marosatherina is the combination of Myros (the name of the village where the celeb rainbowfish was initially discovered), and Atherina, which indicates the genus of fish of the silverside family Atherinidae. Celebes, also known as Sulawesi, is one of the four Greater Sunda Islands in Indonesia.

The IUCN (International Union for Conservation of Nature) has listed the Celebes rainbowfish on the Red List of Threatened Species and deemed it as near threatened. Celebes Rainbowfish are, however, numerous in captivity and heavily farmed in South-East Asia.

The Celebes Rainbowfish was first described in 1936; it has different names, such as Celebes Sailfish and Celebes Sailfin. It is a slender fish whose body colour can change depending on the lighting of your tank. The majority tends to a brown/ yellow hue, with a neon stripe that runs across its back that reflects the blue and green colours. It has pectoral fins that are transparent/white in colours, as well as other fins which are yellow.

Because of their striking colours and their calm temperament, this particular fish can make a great addition to your aquarium; however, caring for these fish is not as easy as one may think. Let’s explore how to take care of the beautiful Celebes!

Celebes Rainbowfish (Marosatherina ladigesi)
Celebes Rainbowfish (Marosatherina ladigesi)

Celebes Rainbowfish Care

Celebes Rainbowfish are very sensitive to any changes in the tank and can die of common diseases, even in the hands of more knowledgeable at fishkeeping. For example, their elaborate fins also mean that they are more susceptible to certain diseases such as fin rot.

Celebes Rainbowfish can also be very shy in the first few days in a new tank, but once they become accustomed to the new environment, they like to swim around freely. As a general rule, tank sizes should reflect the high activity of this species, and we advise you get a tank no smaller than 20 gallons (or 90 liters) which will keep you Rainbowfish happy. Some expert aquarists advise to have a 50-60-gallon (227-272 liters) tank to keep your fishes happy with 6 other specimens. Be careful though: these fish are known to be very good jumpers, so make sure you have a fitted lid to avoid them jumping out!

The Celebes Rainbowfish come from clean and slow-moving waters; as for any other species, the water in the tank should mimic the water of their native geographical area. The Celebs Rainbowfish in known to thrive in tanks where the pH is between 7-8 and the hardness of water is between 12-18 DGH. The tank temperature must be between 22-28 degrees Celsius (or 72–82 degrees Farenheit). In order to achieve these parameters, we recommend that you get an aquarium water test kit to help you monitor the parameters very easily.

Celebes Rainbowfish can survive in salty water (very mild), so you can add a little salt: this will also decrease the chance for them to get a very common infection called Velvet disease (also called gold-dust, rust or coral disease). This illness is caused by the Oodinium parasite. While adding salt to the aquarium, remember these fishes cannot live with too much salt: thus, it is better to add only a half teaspoon of salt per gallon.

Celebes Rainbowfish are tiny creatures, reaching in their adult life the size of 3 inches (7.5 cm). To highlight the beauty of the colours and hues of the Celebes Rainbowfish, we recommend a dark substrate, with smooth surfaces (to avoid injuries). As mentioned before, the Celebes Rainbowfish can be quite timid in the first few days, so they will need many hiding spots- better if these are trees or heavily planted plants. A few plants that provide cover if the fish should choose to retreat include Water Wisteria, Hornwort, and Java Moss. Be sure to leave enough room in the tank for your fish to swim in unobstructed.

Lastly, empower the colours of these fish, you can include some lighting fixtures. Be careful as Celebes Rainbowfish prefer dim lighting and tend to be more active at night.

Feeding Celebes Rainbowfish

One very important thing you need to do to make sure your Celebes Rainbowfish are happy, is a good and balanced diet. Diet is one of the most important parts in taking care of these fish as they can get quite moody and temperamental when hungry. The Celebes Rainbowfish is omnivorous. As omnivores, they will easily accept anything you give to them, including dried and frozen foods, such as daphnia, tubifex, brine shrimp, or blood worms once a week. Apart from that, you can give them flakes, pellet, frozen foods, and tiny vegetable matters, along with some meaty foods.

A fun fact about Celebes rainbowfish is that they have a very small throat, which is why they must be fed smaller portions of food that can be consumed within five minutes. You should feed them at regular intervals, four to five times a day. Also, since the shy nature of these fish, you need to be careful that more aggressive species don’t overpower them and steal all of their food.

Breeding Celebes Rainbowfish

Celebes Rainbowfish sex is difficult to tell when they are juvenile but as they get older males will develop long filament extensions off the fins. The male coloration is also slightly stronger. As with other fish species, the male Celebes Rainbow is larger than its female counterpart and has darker colours. The male second ventral and dorsal fins are also more prominent and spot darker hues than the females.

Breeding Celebes Rainbowfish is not difficult. Celebes Rainbowfish breeding must be done in a separate aquarium with a lot of plants (Milfoil, Cabomba, Riccia, Java moss, and other floating plants) that can make this fish feel comfortable in depositing its eggs. As a general rule, the breeding tank’s pH should be neutral; the water should be slightly salty. Temperature must be dropped slightly (2 degrees) as these fish breed better at lower temperature. Morning sunshine often triggers this species into spawning, so it could be useful to have your breeding tank near a window. The female will become plumper as she fills up with eggs and will scatter these eggs at the bottom of the tank. Once the eggs are laid, you absolutely have to remove the parents before they eat the eggs. The eggs will usually hatch within 7-14 days, the timescale being very dependent on water temperature. For the first four days after they hatch, they feed on their own yolk sack; but after the initial four days, they start swimming and can be fed with commercial foods, finely ground baby brine shrimp, and infusoria. Since the Celebes Rainbowfish fry is small and can be eaten by other fish, so raising them in a separate tank is important until they are big enough to survive in the community tank. The entire process from the egg stage should take around five months.

Tank Mates

Celebes Rainbowfish are peaceful and best kept with non-aggressive groups of 6 to 8 other species that are slow eaters, swimmers, and non-aggressive by nature. Livebearers, Gobies, Halfbeaks, Mollies and other rainbowfishes make good companions to the Celebes Rainbowfish. As this fish does not attack nor defend itself, it is very important to keep them separate from fin nippers and more aggressive fish species. Examples of incompatible fish are: barbs, bettas, cichlids, loaches, and tetras (notorious fin nippers). Caution should always be taken if considering any of these fish for a community tank environment.


On average, Celebes Rainbowfish lifespan is around three to five years. Of course, the lifespan of this fish in your fish tank will depend on how well you nurture it. The Celebes rainbowfish is a schooling fish and lives in a group of a minimum of five/six fishes as they tend to give off more intense colours.

Water quality is paramount for the Celebes Rainbowfish. To maintain the water’s parameters, your tank must have a good filtration system that can get rid of waste build-up; you should as well ensure that 25-50% of the total water is changed weekly. Along with that, it is necessary to keep checking the salt content in water and other factors. Due to their high water sensitivity, it is crucial to look after the water filtration rate and cleanliness to avoid any disease or health problems.

Where to Find Celebes Rainbowfish for Sale

Celebes Rainbowfish are very easy to find in all pet or fish stores. In case you are unable to find them in any of your local stores, you can buy them online. They can be easily found on any online platform. The average price is of about 7.00 USD each.

We hope this guide clearly illustrates how to take care of these beautiful fish so they can enjoy a long and happy life.