Pacific Blue Eye Rainbowfish

The Pacific blue-eye (Pseudomugil signifer) comes from eastern Australia, from Cape York in North Queensland to southern New South Wales’ Burdekin Gap.

These fish are recognizable by their blue eye ring and dorsal fins making them a popular choice for freshwater aquariums.

In this article, we’ll cover everything about caring for Pacific blue-eye rainbowfish, including their freshwater habitats, diet, tank requirements, and more!

Pacific Blue Eye Rainbowfish Characteristics

Scientific NamePseudomugil signifer
SpeciesP. signifer
Water Temperature69.8 – 82.4°F (21-28 °C)
pH Level6.5 and 7.5
Water HardnessdGH range of 5 – 15
Tank Sizeat least a 10-gallon tank
Diet TypeOmnivore
Pacific Blue Eye Rainbowfish Characteristics

Pacific Blue Eye Rainbowfish History

In 1866, Austrian naturalist Rudolf Kner described this fish from a specimen that had been collected in Sydney back in 1858.

Within the northern populations, there are five distinct lineages (or subclades) as follows:

  • One from Ross River and Herbert River
  • The second is from Johnstone, Barron, and Tully Rivers
  • The third is from Mulgrave/Russell River and Trinity Inlet
  • The fourth from Daintree and Mossman Rivers
  • The fifth is from Low Isles and Cape Melville

Also, there are four subclades in the southern populations:

  • The first from the Don, Calliope, Pioneer, and Kolan Rivers
  • The second is from Burnett and Mary Rivers
  • The third from Pine River
  • The fourth is from Clarence River southwards

Pacific Blue Eye Rainbowfish Origin & Habitat

The Pacific blue-eye comes from Narooma in southern New South Wales north to the Rocky River in Cape York peninsula.

These fish species inhabit small, slow-moving streams near estuaries, as well as dune lagoons and salt marshes.

Also, you can find them in brackish and marine waters on some of Queensland’s offshore islands such as Hinchinbrook Island, Lizard Island, Low Island, and Dunk Island.

In the Mary and Dawson Rivers in Queensland, they swim as far upriver as 300 kilometers (185 miles).

Also, there are plenty of them in some areas, such as the Mary River.

Pacific Blue Eye Rainbowfish Behavior

These blue-eyed rainbows live in schools of hundreds to thousands of fish. 

They typically dwell in the middle to the upper water column, near underwater protection, and within 1 meter (3 ft) of the riverbank.

When a school feels threatened, a few individuals accelerate and change direction starting an escape wave that spreads throughout the whole group.

What Are the Features of Pacific Blue Eye Rainbowfish?


The Pacific blue-eyed rainbowfish has an elongated body with pale yellow or olive coloration and silver spots on the operculum and belly.

Also, they have huge scales that are taller vertically than horizontally and big eyes with a blue iris.

There are two dorsal fins, the first of which is in line with or just posterior to the longest pectoral fin ray.

In addition, the forked tail fin has rounded tips, and the bottom and top edges of the tail are edged with white coloration.

For male pacific blue-eyed rainbowfish, the pelvic, dorsal, and anal fins have extended filaments.

At the base of the anterior rays of the anal and rear dorsal fins, there are black marks, and the front is white, while the rear edge is greyish in color.


The male pacific blue eye can reach a maximum length of 3.5 inches (8.8 cm) while females grow up to only 2.5 inches (6.3 cm).


In their natural habitat, these species live approximately 1-2 years. They can survive up to 2-3 years in aquariums, but males can usually live up to 4 years.

How to Care for Pacific Blue Eye Rainbowfish?

a.Water Requirements

1. Water Quality

The Pacific blue-eye can endure a wide range of water salinities, from freshwater to marine settings, according to marine and freshwater research.

However, like other rainbowfish species, they need clean and well-oxygenated water to stay healthy and thrive.

Therefore, you should perform regular water changes of about 20-30% weekly or every two weeks.

2. Water Temperature

Pacific rainbowfish come from wide-ranging habitats, so they can tolerate a wide range of temperatures.

In general, these fish do best in water that is between 69.8 – 82.4°F (21-28 °C).

3. pH Level

Considering their habitat rivers, pacific blue eye rainbows need a slightly acidic to neutral pH level.

The ideal range is between 6.5 and 7.5, but they can live in water with a pH level as low as 5.5.

4. Water Hardness

These beautiful blue-eyed creatures prefer soft to medium-hard water, with a dGH range of 5 – 15.

b.Tank Requirements

1. Tank Size

If you want to keep a single pacific blue-eyed rainbowfish, you’ll need at least a 10-gallon tank.

For a school of 3-4 fish, you’ll need a 20-gallon tank or larger to provide them with enough space to swim and hide in the community aquarium.

2. Decorations

To create a suitable environment for your fish, you should set up a well-planted aquarium with plenty of hiding spots.

You can use live floating plants or artificial plants, as long as they don’t have sharp edges that can injure your beautiful fish.

Pacific Blue Eye Rainbwofish Compatibility

Pacific blue eyes are peaceful species and will get along well with much different fish. However, they don’t get along with other fish of the same species.

Some compatible tank mates include:

  • Danios
  • Tetras
  • Dwarf cichlids
  • Catfish
  • Loaches

Pacific Blue Eye Rainbowfish Diet

In the wild, pacific blue eyes eat a variety of water-based and terrestrial insects, flying insects, such as flies as well as, tiny crustaceans and algae.

They spend their time near the surface looking for dead flying insects and devouring anything smaller than their mouth-gape.

You can feed your pet fish processed, live, frozen, or freeze-dried foods, such as:

  • Flake food
  • Frozen brine shrimp
  • Freeze-dried bloodworms
  • Tubifex worms

Pacific Blue Eye Rainbowfish Breeding

Breeding pacific blue-eye rainbowfish is quite easy, as long as you provide them with the right conditions.

Here are some tips on how to breed them:

  • Set up a separate breeding tank with 50 liters of water
  • Keep your tank at 1/3 salinity for about two weeks before the breeding season begins
  • Install a high-quality filter and an immersion heater
  • Add fine-leaved plants such as Java moss or spawning mops on the floor of the aquarium
  • Increase the temperature by one or two degrees (within the tolerance range of the species)
  • Introduce 1 male and 2-3 female fish into the breeding tank

When the ideal circumstances are met, the pair will release eggs and sperm into the water column.

Then, the males aggressively chase females until they release their eggs by nudging them.

After spawning, you should remove the parents from the breeding tank to avoid them eating their own eggs.

The eggs will adhere to the decoration with tiny fibers. The length of incubation varies between 10 and 21 days depending on temperature.

After hatching, you should feed your baby fish twice a day with mosquito larvae, Daphnia, brine shrimp nauplii infusers, and artemia nauplias.

Last Words

Now that you know everything about the pacific blue eye rainbowfish, it’s time to add them to your aquarium!

Just remember to provide them with the right conditions and tank mates, and you’ll be happy to have a beautiful and peaceful community aquarium.

If you have any questions or tips of your own, please share them in the comments below.

Leave a Reply

Your email address will not be published. Required fields are marked *