The beautiful and delicate Celebes Rainbowfish has been an aquarium favorite since its introduction in the 1930’s!

The Celebes Rainbowfish Marosatherina ladigesi (previously Telmatherina ladigesi) is highly attractive and active fish. It has remained an aquarium favorite since its introduction in the 1930’s. It has with pretty color combinations of blues and golds that are quite pleasing to the eye. Their remarkable fins are wispy and translucent on mature males, with the two dorsal fins on top creating a ‘sail-like’ effect and long filaments streaming out from the tail fin. Additional interest is found in the back half of the fish which is translucent enough for an organ sac to be visible. Besides Celebes Rainbow, it is also known as the Celebes Sailfish and Celebes Sailfin.

These beautiful fish make great additions to a community tank providing a lot of intrigue as they swim around. Yet there is no getting around the fact that these fish are delicate. Celebes Rainbowfish are actually a bit timid by nature, and need a tank with plenty of plant life. Then once they’ve become comfortable, they don’t like a great deal of moving around. They are very sensitive to their surroundings and often die of common, otherwise curable diseases. Even advanced aquarists can struggle to keep this fish healthy.

The Celebes Rainbowfish can be difficult to keep in an aquarium if their needs are not met. They need very clean water and it needs to be medium to hard, but they are sensitive to water changes. Beginners interested in this fish may want to get some experience with easier fish before attempting to keep this rainbow fish.

The Celebes Rainbowfish is listed on the IUCN Red List of Threatened Species as near threatened (NT). Although they are described as being near threatened in the wild, they are numerous in captivity.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Atheriniformes
  • Family: Telmatherinidae
  • Genus: Marosatherina
  • Species: ladigesi
Celebes Rainbowfish – Quick Aquarium Care
  • Aquarist Experience Level: Intermediate
  • Size of fish – inches: 3.0 inches (7.62 cm)
  • Minimum Tank Size: 20 gal (76 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
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Habitat: Distribution / Background

The Celebes Rainbowfish Marosatherina ladigesi (previously Telmatherina ladigesi) was described by Ahl in 1936. It is found in both fresh and brackish water environments in Indonesia, specifically Sulawesi (formerly Celebes). Other common names they are know by include Celebes Rainbow Fish, Celebes Sailfish, and Celebes Sailfin. The Celebes Rainbowfish is listed on the IUCN Red List of Threatened Species: NT- vulnerable. Though described as vulnerable in their natural habitat, they are numerous in captivity.

The Celebes live in fast flowing brackish estuaries where the freshwater rivers flow into the ocean. Because of this turbulence, the waters they live in have a very high oxygen content. The Celebes Sailfish congregate tin floating plants and drift wood. There they hunt under the safety of cover for worms, insects and plants.

  • Scientific Name: Marosatherina ladigesi
  • Social Grouping: Groups – Presumably congregates in schools like other rainbow fishes.
  • IUCN Red List: NT – Near Threatened – Although described as near threatened in the wild, the Celebes Rainbowfish are numerous in captivity.


The Celebes Rainbowfish is a slender fish with very interesting fins. It has two dorsal fins, one that is small and black and the other that is larger and two-toned. Other fins are lemon yellow with black markings. The pectoral fin tips may have black or white tips or may be all the way translucent. Mature males have thread like extensions from their fins. Fin shape will vary, especially on males.

The body color will appear different under different lighting, but is basically brownish yellow with green undertones. There is a neon stripe that runs along the backbone on the back half of the fish that reflects green and blue. The eyes are large. Towards the rear of the fish, scales become increasingly translucent, to the point where individual bones are visible.

  • Size of fish – inches: 3.0 inches (7.62 cm) – This fish will reach 2 to 3 inches (5 – 7.5 cm) in length.
  • Lifespan: 4 years – Can have a life span of about 3 to 5 years when kept in a well maintained aquarium.

Fish Keeping Difficulty

Some will argue that the Celebes Rainbowfish is difficult to keep in an aquarium, but they are not if their needs are met. These fish require very clean, medium to hard water on the alkaline side of neutral. These fish are very sensitive to water changes so make sure weekly water changes are done and water is test frequently.

The Celebes Rainbowfish should never be housed in a tank with fin nippers. Because the fins are so intricate and can be different on each individual, it is often difficult to tell when a fin has been damaged or not. As males mature, fins may divide and change length naturally. This may be tricky to distinguish from splits as a result of injury or disease. Rounded edges to the splits are a good clue not to be alarmed. The intricate fins also mean that they are extra susceptible to certain diseases like fin rot, and these may come without warning, so it is best to always have appropriate medications on hand.

Before purchasing, if possible, wait a few days after new shipments arrive to reduce the chance of mortality from transport shock. When you buy your new fish, ask what the water levels are that they are kept in. If the water is much different then your tank, take extra care to do a slow drip to properly and slowly acclimate your new fish.

  • Aquarium Hardiness: Moderately hardy – Hardy in the right conditions.
  • Aquarist Experience Level: Intermediate – Easy to take care of if all needs are met.

Foods and Feeding

Celebes Rainbowfish are omnivores and that feed on worms, insects, and plants in the wild. In captivity they should be fed a balanced diet including live and processed foods to maintain good health. Buy processed food in small amounts frequently as nutrition in these products quickly deteriorates. Treat them to live foods like tubifex and blood worms or daphnia once a week. Their throats are fairly small so feed smaller foods. Feed these fish several times a day and only what they can consume in under 5 minutes.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet – Small worms.
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day – Feed two to three times daily, but give them only what they can consume in less than 5 minutes.

Aquarium Care

Although small the Celebes Rainbowfish are very active, so need at least 20 gallons or more to swim in. The tank must be very tightly covered to prevent jumps. These fish are sensitive to their water, so the aquarist must be on top of maintenance with a constant regimen of 25-50% weekly water changes being a must.

  • Water Changes: Weekly – 20-30% water change

Aquarium Setup

The Celebes Rainbow needs at least a 20 gallon tank. As with many fish, these rainbow fish will do best and are most effectively displayed in tanks which simulate their natural habitat. They are small fish but need the room because they are very active fish. The tank should be heavily planted. This will make them feel safe as well bring out their colors. But they will also need open spaces to swim between planted areas, and this will give the males the space needed.

These fish do not need salt added but will do fine in low salinity brackish water. A little salt in the water, about a half tsp per gallon, helps out a lot. A few plants that provide dense cover if the fish should choose to retreat include Water Wisteria, Hornwort, and Java Moss. These are good options that will tolerate the salt and harder water the Celebes Rainbowfish likes.The substrate should be a fine gravel. This rainbow fish is very sensitive to water conditions and changes. A good filtration system and moderate current will help with this

A few extra elements in planning their tank will make these fish even more spectacular. They due best in more of subdued lighting, which can be accomplished with bulbs or just add floating plants. The tank can also be in a area where it can get the morning sun for a couple hours a day. A little sunlight hitting the tank will make their colors even more radiant, so position the tank that way if possible.

  • Minimum Tank Size: 20 gal (76 L) – A tank of 50 – 60 gallons is advisable for a school of 6 or more of these active swimmers.
  • Suitable for Nano Tank: Yes
  • Substrate Type: Small Gravel
  • Lighting Needs: Low – subdued lighting
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
  • Range ph: 7.0-8.0
  • Hardness Range: 10 – 20 dGH
  • Brackish: Sometimes – A little salt in the water, about a half tsp per gallon, can help a lot.
  • Water Movement: Moderate
  • Water Region: Middle – The Celebes Rainbow will mostly inhabit the middle of the aquarium.

Social Behaviors

The Celebes Rainbowfish will be quite timid for a few days after their introduction. This Rainbowfish is peaceful and does great in most community tanks. They prefer harder water then most but seem to mix best with other rainbows, livebearers, mollies, halfbeaks, and gobies. They are very active but not aggressive and should never be housed in a tank with fin nippers.

As with most rainbow fish, they can be nervous alone and does best if kept with at least 6 ore more. This will help bring out the males colors as well. Each male should be kept with 2-3 females to get the most color and display out of your Celebes Rainbowfish.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – Groups of 6 or more are preferred.
    • Peaceful fish (): Threat – Does not do well with fin nippers.
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Safe
    • Shrimps, Crabs, Snails: Safe – not aggressive
    • Plants: Safe

Sex: Sexual differences

As juveniles they are difficult to sex, but as they get older males will develop long filament extensions off the fins. The male coloration is also slightly stronger.

Breeding / Reproduction

The Celebes Rainbowfish is not too difficult to breed. A separate breeding tank should be prepared with plenty of fine leaved plants to catch the eggs. Some good ones to try are Cabomba, Mifoil, and Riccia or Java Moss. Some aquarists have trouble getting them to spawn, but slightly cooler temperatures may do the trick. A spawning mop can be used in place of the plants. The parents will distribute the eggs and they will hatch in about a week.

Parents should be removed before the eggs hatch, although the eggs are large the fry are small. Once hatched, feed them commercially prepared fry foods. Do not introduce the young fish into the main tank until they are safely large enough not to be eaten. This could be as long as 5 months.See an overview of how to breed Rainbow fish in Breeding Freshwater Fish.

  • Ease of Breeding: Moderate

Fish Diseases

Rainbowfish are extremely hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won’t have to deal with health problems or disease. Remember anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.

A good thing about rainbow fish is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Rainbow fish the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. Stressed fish are more likely to acquire disease.

For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments. This is a great source for information on disease and treatments. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. Rainbow fish are very resilient.


The Celebes Rainbowfish is readily available in pet stores and online. This fish is usually moderate in priced, though a bit more than some of the other rainbow fish species.