Max Size: 7cm

Pacific Blue Eye Rainbowfish (Pseudomugil signifer)

The Pacific Blue Eye Rainbowfish is a peaceful, active and relatively hardy addition to any nano, planted or smaller species community aquarium. The males exhibit beautiful colouration and finnage, which is more pronounced during frequent and exciting sparring bouts that occur throughout the day.

Ideal tankmates for Pacific Blue Eye Rainbowfish could include other Pseudomugil Rainbowfish such as the Honey Blue Eye, Red Neon Blue Eye and Spotted Blue Eye Rainbowfish. However, it should be noted Pseudomugil species can hybridise, so if you aim to breed this fish and maintain its purity, other smaller Rainbowfish such as the Celebes Rainbowfish, Ornate Rainbowfish or Dwarf Neon Rainbowfish will make more suitable tank mates.

Other possible tankmates can include other peaceful species of similar size, disposition, and water requirements such as Peacock Gobies and Neocaridina Shrimp which can also make good tankmates; however it is worth bearing in mind small Shrimplets may fall prey to these fish.

Pacific Blue Eye Rainbowfish are a shoaling species; therefore, it would be better to keep them in a group of at least 8 to 10 individuals, preferably more. Maintaining these fish in such numbers will not only make them less nervous but will also result in a far more effective, natural-looking behaviour.

Males will also display some fascinating behaviour and show off their best colours as they compete for female attention.

You would preferably need to keep these Rainbowfish in a spacious aquarium as the males are somewhat intolerant of each other when they are in spawning condition.

Sometimes, the most dominant males can harass subdominants, who may fall victim to the stress if the aquarium is too small. Therefore, keeping them alongside other aquatic species is usually recommended to disperse aggression.

Pacific Blue Eye Rainbowfish have elongated partly transparent bodies and are pale yellow or olive with a silver operculum and stomach. Their scales are relatively large and are longer vertically than horizontally. Their eyes are large and they have a blue iris. These Rainbowfish have two dorsal fins; the first is typically in line with or just posterior to the longest pectoral-fin ray. In addition, they possess a forked tail fin with rounded tips, and the bottom and top edges of the tail fin are bordered with white.

The males usually have extended filaments on their dorsal, pelvic and anal fins. In addition, there are black markings on the base of the anterior rays of the anal and rear dorsal fins, the front is sometimes white, and the back edge is greyish. The male's fins may turn orange during the breeding season.

Quick Facts
Scientific NamePseudomugil signifer
Year Described1866
Other NamesNone
Aquarium LevelMiddle - Top
Best kept asGroups 8+
Lifespan2 - 3 years
Water Parameters
Water TypeFreshwater
PH6.5 - 7.5
GH5 - 15
TDS90 - 268
75 - 79℉
23.9 - 26.1℃

Photos of the Pacific Blue Eye Rainbowfish

Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish
Pacific Blue Eye Rainbowfish


Pacific Blue Eye Rainbowfish (Pseudomugil signifer) Freshwater Aquarium Fish Profile & Care Guide

Natural Habitat

Pacific Blue Eye Rainbowfish have been collected in Sydney, New South Wales state, and eastern Australia. Their range stretches along most of the country's eastern coastline, from Merimbula Lake in southern New South Wales, close to the border with Victoria state, to Embley River in far North Queensland in Australia.

These Rainbowfish are generally found close to the sea; however, their habitats are incredibly variable, and this species has been recorded in fully marine conditions and pure freshwater environments.

Pacific Blue Eye Rainbowfish usually inhabit swamps, coastal mangrove creeks, and salt marshes. Freshwater habitats typically include lowland swamps or forest streams with clear water, although some inhabit acidic, tannin-stained, black waters. These fish are also abundant in the artificial canals typical of residential zones in the Gold Coast in southern Queensland.

Merimbula Lake

What to feed the Pacific Blue Eye Rainbowfish

Pacific Blue Eye Rainbowfish feed primarily on suspended or floating phytoplankton, zooplankton and invertebrates in nature. Therefore, in the aquarium, you should endeavour to offer them food of a suitable size.

Ideally, much of this species diet should include live and frozen foods such as brine shrimp, bloodworm, microworm and daphnia. However, they are an unfussy eater and readily accept small dried foods such as crushed flake and micropellets.

How to sex the Pacific Blue Eye Rainbowfish

It is quite easy to differentiate between male and female Pacific Blue Eye Rainbowfish. Mature males are more brightly coloured and display longer finnage than females. The male is also a little larger and possesses black markings on their anal and dorsal fins.

How to breed the Pacific Blue Eye Rainbowfish

Pacific Blue Eye Rainbowfish are egg layers that present no parental care and will often consume their eggs and fry if given an opportunity. However, in a well-decorated aquarium, some may survive.

Spawning is more likely to occur in slightly higher temperatures. Females deposit a few eggs daily for several days, attaching them to aquatic vegetation or other substrates by sticky threads. Individual males will also mate with multiple females during a single day, and spawning usually continues throughout daytime hours during warmer weather.

In nature, these Rainbowfish display a seasonal reproductive cycle corresponding with the onset of the wet season, around October to December, when aquatic vegetation and food are at their most abundant.

Spawning usually occurs during daylight hours, with a burst of activity late morning to early afternoon. Breeding can occur throughout the year in the aquarium if the temperature is kept at the same values.

You can use two methods to spawn these fish; the first involves isolating a small group of 6 to 8 individuals or a single male and two or three females into a separate breeding tank with an air-powered sponge filter and a spawning medium such as nylon mops or aquatic moss. You will need to check this daily, and if you find any eggs, you will need to move them into a separate rearing tank for incubation and hatching.

Another method you may use is maintaining a colony of adults in a more extensive, fully-decorated set-up that should allow some fry to survive if well-planted. However, the fry initially spends most of its time close to the water's surface. Therefore, it is advised that you attach aquatic mosses to decor high up in the aquarium or use floating plants with long roots, as this will produce the most favourable results.

The second approach is usually less productive but more straightforward and reliable as established and planted aquariums facilitate relatively stable water conditions. In addition, the resident microfauna can create a valuable early food source for the fish fry.

The incubation period for these Rainbowfish is usually between 10 and 21 days depending on temperature, and the fry can accept baby brine shrimp, microworm, and similarly-sized foods immediately. You can also raise them on good quality, powdered dry products. It would be best if you offered your fry small meals at least twice a day.

It would be beneficial to remember that aged water can result in high mortality, so performing regular, small water changes are essential. Any uneaten food needs to be removed and should not be allowed to accumulate in the rearing tank.

Other Rainbowfish of interest

Banded Rainbowfish(Melanotaenia trifasciata)
Boesemans Rainbowfish(Melanotaenia Boesemani)
Celebes Rainbowfish(Marosatherina ladigesi)
Dwarf Neon Rainbowfish(Melanotaenia praecox)
Forktail Blue Eye Rainbowfish(Pseudomugil furcatus)
Honey Blue Eye Rainbowfish(Pseudomugil Mellis)
View all Rainbowfish
Date Added: 05/08/2021 15:22:04 - Updated: 14/03/2022 14:11:42