Ramu Rainbowfish

The Ramu Rainbowfish shows a close relationship with the Spotted Rainbowfish, evident in their similar size and some coloration elements. Adult individuals can reach approximately 6 cm in length. The dorsal coloration ranges from greenish-brown to purple hues. Orange stripes run along the lateral line on the sides. A bluish sheen is visible on the belly, and up to a dozen black spots can be seen. With age, these spots become less pronounced. It is important to note that this vibrant coloration is primarily characteristic of males, while females appear more subdued.

The species is endemic to Papua New Guinea. In nature, it inhabits tributaries of the Gogol River near Madang, and is also found in the Ramu River basin. The fish inhabit freshwater bodies, primarily small rivers and streams with flowing water, where they prefer areas with dense aquatic vegetation.

This fish is distinguished by its peaceful and active nature. It coexists well with its own kind and with other species of similar size and temperament. However, it is advisable to avoid housing them with slow-moving fish, as the more agile Rainbowfish may outcompete them for food.

For a school of 6–8 individuals, an aquarium of 60–80 liters will be optimal. The aquarium setup can be anything, the main thing is to provide enough free swimming space and several shelters. These can be dense thickets of plants, including floating ones. For long-term keeping, maintaining stable water parameters becomes crucial. Medium hardness with a neutral or slightly alkaline pH level is considered the most comfortable. Aquarium maintenance is standard and similar to caring for other freshwater fish. Essential procedures include: weekly partial water changes, removal of organic waste, and regular equipment checks. In terms of feeding, the fish is unpretentious. It will readily accept most common types of food: dry, freeze-dried, frozen, and live.

This fish is undemanding regarding food. It readily consumes a variety of foods, available in dry, freeze-dried, frozen, or live forms.

Breeding occurs through spawning. To stimulate spawning, breeders are fed live or frozen foods abundantly for two weeks. Fine-leaved plants or special synthetic spawning mops are placed in the breeding tank. Eggs are laid in portions over several days. After the process is complete, the parents must be removed to prevent them from eating the offspring. Fry hatch after 48 hours and begin to swim freely, after which they are fed infusoria or micro-food, gradually transitioning to Artemia nauplii.

No specific diseases exclusively characteristic of this species have been identified. Like other members of the family, Ramu Rainbowfish are sensitive to water quality and susceptible to common infections if keeping conditions are violated. The main risks are associated with the accumulation of organic compounds, causing bacterial skin and fin lesions, as well as parasitic invasions when new individuals are introduced without prior quarantine. To prevent diseases, it is necessary to maintain stable environmental parameters and avoid sharp temperature fluctuations. Water purity is a key factor in protecting immunity, so regular water changes and effective filtration are mandatory. If signs of stress or damage appear, the level of nitrogenous compounds should be checked, and the fish should be provided with peace in an aquarium with good aeration.

When selecting individuals, attention should be paid to the overall activity of the fish and the cleanliness of their skin. Healthy rainbowfish should show interest in food, have bright coloration without spots, ulcers, or fin damage. Avoid purchasing fish that stay at the surface, breathe heavily, or appear emaciated. It is recommended to acquire a group of 6 or more individuals, as fish kept alone are prone to stress and become timid.