Gertrude Fish


Pseudomugil gertrudae, commonly known as the spotted blue-eye rainbow fish, adds stunning color and variety to aquariums worldwide. Native to Papua New Guinea and northern Australia, these graceful fish have thrived under captivity since their introduction.

Peaceful species flourishing in vegetation waterways prefer muddy bottoms with clear waters above. Feeding them a balanced diet consisting of high-quality dry and flake food and small live or frozen foods will ensure optimal health and vibrant colors in these peaceful creatures.

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These captivating fish make an eye-catching addition to any aquarium, with vibrant hues spanning blues, yellows, and oranges that reflect light beautifully as they move throughout your tank. Their mesmerizing bodies shine like jewels as their beautiful bodies reflect it beautifully back at you as they glide by.

Pseudomugil Gertrude, commonly called the Gertrude fish, is an exotic variety native to Papua New Guinea and Australia that aquarium owners love due to its vibrant colors and playful personality. Aquarists especially adore these fascinating fishes for their rich hues and engaging characters.

This fish species thrives in shallow, muddied waters and makes an excellent addition to a community tank, coexisting peacefully with similar-sized and temperament fish species.

Though Gertrude fish can be relatively easy to care for, it is still vitally important to provide it with a balanced and nutritional diet comprised of high-quality dry and flake foods and live/frozen meaty treats to promote its well-being and vibrant coloration. Achieving this balance will help it flourish while keeping its health intact.

Gertrude fishes are small, slender fish characterized by bright blue eyes and vibrant colors that shimmer as light passes through their scales. With semi-translucent bodies that reflect light from passing through, these beautiful blue iridescences reflect light beautifully when passing over scales. Furthermore, they display numerous finnage features visible on anal, dorsal, and pectoral fins for added complexity and an eye-catching aesthetic.

Their oblong eyes are on an upturned face, ideal for grabbing food off the water’s surface. Unlike many members of the rainbowfish family, these fishes do not feature scales on their heads but boast smooth, leathery skin instead.

Because of their small, sleek bodies, fish can move gracefully through the water. Furthermore, their round mouths make them great at grabbing food from its surface.

These beautiful fishes typically live in an aquarium for 3 to 5 years and quickly become the focal point. To maximize their potential, keep them in an aquarium with heavily planted aquatic life while providing a nutritious diet. By creating an ideal environment where they can flourish, this rare beauty will keep giving back with incredible color displays for years to come!


The Gertrude Fish is an attractive freshwater species known for its vibrant mix of blues and yellows. Native to Australia, this fish has become increasingly popular as an aquarium fish due to its sleek torpedo shape and beautiful hue. Aquarium fish enthusiasts frequently keep these as they are found throughout various aquatic habitats, including reefs, shallow reefs, shallow pools, and muddy substrate. In particular, this fish prefers shallow waters near rivers with more than 60cm (2ft). These areas typically range in depth between 60 cm (2ft). When living near larger rivers with overflows from larger rivers with pH levels between 5.2 6.7.

These fish feature sleek torpedo-shaped bodies that help them move swiftly through the water, with upturned mouths designed to capture prey at its surface. Omnivorous in nature, they feed on both algae and small crustaceans like daphnia or brine shrimp.

This species of fish is a schooling fish and thrives when kept with similar-sized and temperament individuals in a tank, as this will reduce nervousness and allow it to display its vibrant hues more freely. Males, in particular, stand out with their impressive dorsal, pectoral, and anal fins shown for display while asserting dominance over their territories and drawing females closer.

Pseudomugil Gertrude fish in nature usually spawn in clear, shallow streams or rivers near overhanging vegetation, where males show their bright colors and long fins to compete for female attention. Once one does accept, both parents will swim together, fertilizing each other’s eggs until the eggs hatch, at which time fry must be fed with infusoria and commercial fry food to thrive.

Gertrude fish typically live for one year. These easy-care aquarium fish make an excellent choice for beginners looking to witness their incredible transformation from tiny fry into stunning adults.


Pseudomugil Gertrude, or Spotted Blue Eye Rainbowfish or Gertrude’s Rainbowfish, is an exquisite tropical fish native to northern Papua New Guinea and Australia. Due to its vibrant hues, calm nature, and hardiness, have long been prized among aquarists as a freshwater species.

Like other rainbowfish species, Gertrude fishes are omnivorous fishes that feed on plant and animal material. Their ideal diet includes high-quality flake, frozen foods, and smaller live or freeze-dried meaty items. Although it’s generally safe to keep alongside non-aggressive tankmates, aggressive or territorial species should be avoided to prevent stress or injury to themselves or the fish they share space with.

Gertrude fishes can be found throughout freshwater habitats such as creeks, swamps, marshes, rainforest streams, lily lagoons, backwaters, and slow-moving rivers with overflow channels adjacent to larger rivers. Aquarium environments that create similar environments for these fishes should provide them with floating plants, vegetation, and dark or muddy substrate. They tend not to thrive when kept together in large schools but will do well in an established aquarium setting.

Male guppies tend to be more colorful and intricately patterned than their female counterparts, with longer finnage on both the pectoral and anal fins. Males sometimes flail their dorsal and pectoral fins to attract mates or establish territory; these displays may also show off fan-like dorsal and anal fins that become brighter with maturity.

Gertrude fishes differ from other rainbowfish by not eating their eggs, making them an excellent choice for freshwater breeders wanting to produce their broods. Their spawning continues continuously while the fry can be fed on infusoria or commercially available rainbowfish fry food.

Gertrude fishes require at least 10-gallon tanks to thrive, although 20 is recommended if breeding or keeping tankmates with them. Gertrudes are hardy fish that can tolerate higher temperatures as well as some levels of water hardness; however, regular water changes will be needed to maintain optimal tank parameters and ensure your success with keeping gertrude fish.


Gertrude fish make beautiful additions to any aquarium yet require specific care to remain at peak health and coloration. As they’re shoaling species, keeping at least six individuals together would be optimal; additionally, they’ll show their best colors when held in dense plants.

As they tend to be relatively peaceful with other fishes of similar size, Gertrude fish may become overshadowed and intimidated by more aggressive tank mates. A tank with ten 10-gallon capacity or larger should provide them with ample room to thrive. Being an omnivorous species, they will readily accept high-quality flake foods, but it is wise to supplement these regularly with meaty frozen and live food items to prevent outcompeting for sustenance from more dominant tankmates.

An aquarium should provide the Gertrude fish with a relaxing environment and should be maintained between 72-79 degrees Fahrenheit, providing plenty of ventilation and frequent water changes to maintain high-quality water quality. Furthermore, a soft substrate with plenty of hiding spaces must also be provided with an efficient filtration system capable of accommodating their large waste production.

Like other rainbowfish species, Gertrude fish are susceptible to infections caused by poor water conditions, including skin flukes, Ichthyobodo disease, and general bacteria infections. Regular aquarium maintenance and water changes should be conducted to minimize their risks of infection and ensure their well-being in an aquarium environment.

Pseudomugil gertrudae), also known as the Spotted Blue Eye Rainbowfish, can typically be found in shallow, marginal areas of freshwater habitats such as swamps, marshes, rainforest streams, lily lagoons, backwaters, and overflows of larger rivers. They prefer shallow waters with slow currents to hide from predators.

This charming fish can easily be distinguished from others by its bright blue eyes and shimmering body. Males feature bolder hues with more ornate pectoral and anal fins, while females display subtler tones and shorter, simpler fins. Males will flare their dorsal and pectoral fins when ready to reproduce, and females usually do so less frequently than their counterparts.