The Celebes Rainbowfish, Marosatherina ladigesi, is a distinctive freshwater fish from Sulawesi, Indonesia. Although it is commonly called a rainbowfish, it belongs to the sailfin silverside family Telmatherinidae. Its slim silver body, blue sheen and yellow-edged fins give it a delicate appearance that becomes especially impressive when a group is kept in a well-lit, planted aquarium.

Native Range and Natural Habitat

Celebes Rainbowfish are native to Sulawesi, historically known as Celebes. In the wild they occur in clear streams and related freshwater habitats where vegetation and open swimming areas occur together. They are active midwater fish, so an aquarium should provide both plant cover and plenty of unobstructed space.

Size and Aquarium Requirements

Adult Celebes Rainbowfish can reach around 8 cm, although many aquarium specimens remain somewhat smaller. They should be kept as a group rather than singly. A longer aquarium is preferable because these fish are active swimmers and display more naturally when they have room to move as a shoal.

A planted layout with open central swimming space works well. For ideas on balancing plants with usable swimming room, see our aquascaping techniques and ideas guide.

Water Conditions

This species prefers warm, clean and reasonably mineral-rich water. A temperature around 24–28°C is suitable, with approximately 25°C being a useful target. Neutral to moderately alkaline water is generally preferred, around pH 7.0–8.0. Stability is more important than chasing an exact number, so avoid sudden changes in temperature or chemistry.

Good filtration and regular partial water changes are important. If you are new to testing aquarium water, our aquarium water chemistry basics guide explains the key parameters.

Diet and Feeding

Celebes Rainbowfish are omnivorous. Feed a varied diet based on quality flakes or small pellets, supplemented with frozen or live foods such as brine shrimp, daphnia and small insect larvae. Foods should be appropriately sized for their relatively small mouths. Several small meals are better than repeatedly overfeeding the aquarium.

Sexing Celebes Rainbowfish

Mature males are usually more colourful and develop longer, more elaborate fins. Females tend to have a fuller body and less dramatic fin development. Keeping several individuals allows normal social displays and gives males opportunities to show their best colour without focusing all attention on one fish.

Breeding

Celebes Rainbowfish are egg layers and can be bred in aquariums. A well-conditioned group may spawn among fine-leaved plants or spawning mops. Adults may eat eggs, so breeders often move the spawning material to a separate hatching aquarium. Newly hatched fry require very small foods before they are large enough to accept newly hatched brine shrimp.

Community Tank Compatibility

This is generally a peaceful community species. Good companions include similarly sized, non-aggressive fish that appreciate comparable water conditions. Suitable choices can include Harlequin Rasboras and peaceful rainbowfish of an appropriate size. Avoid large predators, persistent fin nippers and very slow feeders that may be unsettled by constant activity.

Ease of Care

Care is moderate. The species is not especially difficult once established, but it benefits from stable water, a proper group and consistent maintenance. It is better suited to aquarists who already understand cycling and routine water care than to someone setting up their first aquarium on the same day.

Species Variations and Albino Forms

There are no widely established albino Celebes Rainbowfish varieties in the aquarium trade. Colour intensity can vary with genetics, sex, condition, diet and lighting, but unusually pale individuals should not automatically be described as albino. Related Sulawesi silversides exist, but they are separate species rather than colour variations of Marosatherina ladigesi.

Frequently Asked Questions

How many Celebes Rainbowfish should be kept together?

Keep a group rather than a single fish. Six is a sensible minimum, while a larger group can produce more natural schooling and display behaviour when aquarium size allows.

Are Celebes Rainbowfish suitable for beginners?

They can be kept successfully by newer aquarists, but they are best for someone comfortable maintaining stable water quality and a fully cycled aquarium.

Do Celebes Rainbowfish need a planted tank?

Plants are strongly beneficial because they provide security and spawning sites, but the tank should also retain plenty of open swimming room.