Spotted Blue-eye

Adults of this fish reach a length of approximately 4 cm. Their coloration is predominantly yellow, and their translucent fins have a whitish tint and are adorned with black speckles. One of their most striking features is their bright blue eyes, which gave the fish its second name. Sexual dimorphism is not very pronounced: males are generally slightly larger and their coloration is more intense than that of females.

The natural habitat of these fish covers northern Australia, the southern regions of New Guinea, as well as numerous islands located in the Arafura and Timor Seas. They prefer to live in shallow, slow-flowing rivers, swamps, and lakes. Spotted Blue-eyes have a particular fondness for areas with abundant aquatic vegetation and plenty of driftwood. Often, the water in these biotopes has a brownish tint due to the saturation of organic matter.

These fish are distinguished by their calm and peaceful nature. They get along well with other species of similar size and temperament. It is recommended to keep them in shoals of at least 8–10 individuals of both sexes. It is believed that the best results in keeping them are achieved in a species-specific aquarium, where the only neighbors are small freshwater shrimp.

For comfortable keeping of a shoal of 8–10 Spotted Blue-eyes, an aquarium of at least 40 liters is required. For decoration, it is recommended to use dense groups of plants, while leaving open areas for swimming. The presence of additional shelters, for example, in the form of driftwood, will be very useful. The choice of substrate depends on the needs of the plants. It is important to note that these fish do not like bright light and strong currents, so the lighting and filtration system should be chosen with these features in mind. Water parameters for Pseudomugil gertrudae should be slightly acidic in pH and have low hardness. To maintain stable water quality, it is necessary to change 15–20% of the volume weekly and ensure an effective filtration system.

Any appropriately sized food, whether dry, frozen, or live, fits well into the diet of Spotted Blue-eyes. However, preference should be given to live foods such as daphnia, artemia, or small bloodworms.

Breeding the Spotted Blue-eye does not present any particular difficulties and does not require special preparations, as spawning can occur year-round. Spawning behavior can be triggered by raising the water temperature to the upper limits of the acceptable range (26–28°C). Females attach their eggs among dense plant thickets. Fine-leaved and low-growing species, such as Java moss, or special artificial spawning substrates, are excellent for this purpose. The dominant male typically fertilizes several clutches of eggs from different females. It is important to note that these fish lack parental instincts and may eat their own eggs immediately after spawning. To preserve the offspring, fertilized eggs should be promptly transferred to a separate incubator, where the water parameters will be identical to the main aquarium. The fry will remain there until they reach a sufficiently large size, which usually takes about six months. The incubator is equipped with the same equipment as the main aquarium, with the exception of the filtration system. It is preferable to use a simple air-driven sponge filter, which will provide sufficient water purification and prevent accidental suction of the fry. The incubation period lasts approximately 10 days; the duration depends on the temperature. In the first days after hatching, the fry will need micro-food, such as infusoria. After about a week, they can begin to be fed artemia nauplii.

Health problems in these fish arise only in the presence of injuries or keeping in unsuitable conditions, which leads to a weakening of the immune system and the subsequent occurrence of various diseases. At the first signs of illness, it is necessary first to check the water parameters for exceeding permissible values or the presence of toxic substances (such as nitrites, nitrates, ammonia). If deviations are found, all indicators should be normalized, and then treatment should begin.

When selecting individuals, attention should be paid to their activity and the integrity of their fins, which should be spread out in healthy fish. Avoid specimens with signs of emaciation, damaged scales, or body film. It is important to assess the behavior of the shoal in the store: healthy fish show curiosity, swim actively, and demonstrate species-specific interactions, rather than hiding in corners or near the surface. Since the species is sensitive to sudden changes in conditions, it is recommended to ask the seller about the water parameters in which the fish are kept to minimize stress during adaptation to a new aquarium.