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Maximum size : 2.5 cm

Spotted Blue Eye Rainbowfish - Pseudomugil gertrudae : Complete Fish Profile & Care Guide

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The Spotted Blue Eye Rainbowfish, (Pseudomugil gertrudae) is an exquisite and peaceful species that thrives in groups. It is crucial to keep these fish in numbers, or else they may become skittish and intimidated by other inhabitants of their aquarium. While they are not the best fit for a community tank, they can be kept alongside other fish with similar requirements, size, and disposition. The optimal environment for the Spotted Blue Eye Rainbowfish entails a densely-planted aquarium, making it an excellent addition to a carefully aquascaped tank. Providing some floating plants and driftwood roots or branches not only adds to the natural appeal of the habitat but is also appreciated by the species. Ensuring that the water is well-oxygenated with a suitable flow is advisable. It is critical not to add this fish to a biologically immature aquarium, as it is susceptible to abrupt shifts in water chemistry, which could be detrimental to its well-being. These fish have a compressed and elongated body that shimmers with a semi-transparent blueish-silver hue, sometimes even displaying a radiant golden-yellow sheen. Their two close-together dorsal fins reveal a visible swim bladder. However, what sets this species apart are the bright yellow, orange, or orangey-red tips of their pectoral fins and the white-bordered anal, dorsal, and tail fins with oblong or rounded dark spots scattered all over them. The Spotted Blue Eye Rainbowfish boasts a fascinating latticework pattern over its body, with several rows of black-bordered scales. All scales except for those of the mid-ventral and mid-dorsal rows have a spot that forms about six rows of irregular lines. The mid-lateral stripe seems to be continuous from just below and in line with the start of the first dorsal fin to the caudal peduncle. There are considerable differences in colouration, body size, finnage size, and shape among these species. It is worth noting that if you intend to breed these fish, avoid keeping them with other Pseudomugil species like the Red Neon Blue Eye Rainbowfish as they can hybridize.

Spotted Blue Eye Rainbowfish Photos

Sexual Dimorphism

Distinguishing between the male and female Spotted Blue Eye Rainbowfish is quite straightforward. Females are characterized by a deeper body structure, while the males possess larger dorsal, pelvic, and anal fins with elongated filaments on the first dorsal and pelvic fins. Males also exhibit more vivid hues and spots on both their fins and bodies.
Featured Male
Featured Female
Male Female

Quick Facts

Scientific NamePseudomugil gertrudae
Year Described1911
Other NamesSpotted blue-eye
OriginsPapua New Guinea Australia
Max Size2.5 cm
Aquarium LevelMiddle
DifficultyBeginner - Intermediate
Best kept asGroups 5+
Lifespan3 - 5 years

Water Parameters

Water TypeFreshwater
PH4.5 - 7.5
GH5 - 12
TDS90 - 215
73 - 86
22 - 30

Natural Habitat

The Spotted Blue Eye Rainbowfish can be found in the rivers and tributaries draining into the Gulf of Carpentaria in Australia, including the Calvert and Nicholson Rivers. They are also known to inhabit islands such as Melville, Bathurst, and Groot Eylandt, as well as smaller islands in the Torres Strait of Papua New Guinea and northern Australia. These stunning fish are commonly found in shallow, slow-moving areas with an abundance of vegetation, such as streams, billabongs, creeks, lakes, and swamps. They are often seen among macrophytes, submerged woody structures, fallen branches, and leaf litter, making for a truly mesmerizing sight. The Spotted Blue Eye Rainbowfish is also adaptable to a range of water conditions. In some areas, the water may be crystal-clear, while in other regions, the water may be stained dark brown with tannins, with a very low pH and dissolved nutrients. Despite these varying conditions, the Spotted Blue Eye Rainbowfish continues to thrive and enchant with its remarkable beauty and unique behaviour. Join us on a journey to discover the captivating world of the Spotted Blue Eye Rainbowfish and witness firsthand the stunning diversity and resilience of this amazing species.


The Spotted Blue Eye Rainbowfish is a fascinating egg-scattering species that requires specific conditions for successful breeding. To maximize the chances of successful spawning, maintain a warm temperature in the aquarium. Female Rainbowfish will lay a few eggs each day on aquatic plants or other substrates using sticky threads. Meanwhile, a single male can mate with multiple females in one day, with spawning typically occurring during the daytime, especially in warmer periods. In the wild, these fish display seasonal reproductive cycles, coinciding with the onset of the rainy season in October-December when food and vegetation are abundant. However, in captivity, breeding can take place year-round with the right conditions. There are two breeding methods to try: first, a small group containing one male and two or three females can be placed in a breeding tank with plenty of plants or a spawning mop and an air-powered sponge filter. Secondly, a larger group of adults can be housed in a fully-decorated setup that is heavily planted, providing a hiding place for fry. After the eggs are laid, they will hatch in approximately ten days, depending on the temperature. For the first five days, the fry will require microscopic food such as unicellular organisms or high-quality powdered food. Then, freshly hatched brine shrimp or microworms can be introduced and given twice a day. To prevent high mortality rates, ensure that uneaten food does not accumulate and perform small water changes regularly in the rearing tank. Successful breeding can be a challenging but rewarding experience for the dedicated aquarist.

Diet & feeding

To maintain optimal health, it is important to provide a balanced diet for the Spotted Blue Eye Rainbowfish. While they are not particularly selective eaters, it is recommended to include high-quality flake food, as well as frozen or live food such as brine shrimp and bloodworms, which are preferred over dry food. It is essential to ensure that the food particles are of suitable size, as these fish have small mouths and may experience difficulty swallowing larger particles. A balanced and varied diet will not only keep your fish healthy but will also enhance their natural coloring and promote their overall well-being.\r\n

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