Dusky Millions Fish - Phalloceros caudimaculatus : Complete Fish Profile & Care Guide
Table of contents
Introduction
The Dusky Millions Fish (phalloceros caudimaculatus) is an aesthetically appealing and resilient species, making it relatively popular among aquarium enthusiasts. These fish are best kept in a species-only aquarium, forming a group of 6 to 8 individuals, with a recommended ratio of two to three females per male to mitigate excessive male harassment. While they are peaceful, the Dusky Millions Fish can also coexist with other calm species that thrive in cooler water conditions, such as Danios, White Cloud Mountain Minnows, and Ricefish. However, caution should be exercised when selecting tankmates to avoid species with delicate fins or larger, more aggressive fish that may compete for resources.
Creating an ideal habitat for the Dusky Millions Fish involves maintaining a heavily planted aquarium with gentle filtration and water movement, replicating their natural surroundings. It is advisable to choose robust or fast-growing plant species, as softer-leaved plants may be grazed upon, although this may not pose a significant issue if the fish are well-fed. The addition of floating plants, such as duckweed or water lettuce, can help regulate lighting conditions in the aquarium. Given their sensitivity to water chemistry fluctuations, any adjustments to water parameters should be implemented gradually to ensure the well-being of these fish. It is also recommended to exercise caution during water changes, opting for smaller and more frequent changes while gradually introducing new water.
The Dusky Millions Fish exhibits a silvery body with a distinct, elongated dark vertical mark beneath the dorsal fin and black patches on their fins. Male individuals feature numerous irregular black blotches and spots across their bodies, while females typically display fewer markings. In some cases, individuals may exhibit a slight yellowish tinge in their body colouration. These distinct physical characteristics contribute to the overall allure and visual appeal of this species.
Dusky Millions Fish Photos
Sexual Dimorphism
Distinguishing between the male and female Dusky Millions Fish is a straightforward task. Females can be easily identified by their larger size compared to males and exhibit fewer blotches on their bodies. On the other hand, males are smaller in stature, display a greater degree of speckling throughout their bodies, and possess a distinct gonopodium—an anatomical feature used for reproduction.
Quick Facts
| Scientific Name | Phalloceros caudimaculatus |
|---|---|
| Year Described | 1868 |
| Other Names | Speckled mosquitofish, one-spot livebearer, Speckled Livebearer, Leopardfish |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Cyprinodontiformes |
| Family | Poeciliidae |
| Genus | Phalloceros |
| Origins | Brazil , Argentina , Uruguay , Paraguay |
| Max Size | 6 cm |
| Temperament | Peaceful |
| Aquarium Level | All Levels |
| Difficulty | Intermediate - Advanced |
| Shoaling | No |
| Best kept as | Groups 6+ |
| Diet & Feeding | Omnivore |
| Reproduction | Livebearer |
| Average Lifespan | Up to 2 Years |
Water Parameters
| Water Type | Freshwater/Brackish |
|---|---|
| pH | 6.0 - 8.0 |
| GH | 5 - 20 |
| TDS | 90 – 447 |
| ℉ | 64 - 72 |
|---|---|
| ℃ | 17 - 22 |
Natural Habitat
The Dusky Millions Fish is a species native to the northeastern regions of Brazil, including the states of Rio de Janeiro and Paraguay, as well as parts of northern Argentina and Uruguay in South America. However, due to their effectiveness in controlling mosquito larvae, these fish have been intentionally introduced to various countries, resulting in their establishment as an invasive species in many regions.
In their natural habitat, these fish inhabit slow-flowing streams, rivers, and ponds that are typically characterized by dense vegetation. Their adaptability allows them to thrive in various environments, demonstrating their ability to acclimate to diverse conditions. In some cases, populations of the Dusky Millions Fish have even been observed in slightly brackish water, showcasing their remarkable resilience and versatility.
Breeding
The breeding process of the Dusky Millions Fish is relatively straightforward. Following successful fertilization, the female undergoes a gestation period of approximately four weeks, influenced by temperature variations. Subsequently, she will give birth to a brood of up to 50 free-swimming fry, although younger females may produce fewer offspring. While the adult fish generally do not pose a threat to the young, it is crucial to separate the fry from other fish species within the same aquarium, as they are likely to prey on the vulnerable fry. By providing a well-planted aquarium with ample hiding places, a few fry can be expected to survive to adulthood. To nourish the newborn fry, a suitable diet includes finely crushed dried food, baby brine shrimp, and microworms, which can be introduced immediately after birth.
Diet & Feeding
The Dusky Million Fish demonstrates a versatile and adaptable feeding behaviour. In their natural habitat, these fish consume a varied diet consisting of algae, small insects, insect larvae, and crustaceans. In an aquarium setting, offering a diverse selection of food is recommended to ensure their nutritional needs are met. This includes providing frozen, live, and freeze-dried options such as baby brine shrimp, vitamin-enriched brine shrimp, mini-bloodworm, and white mosquito larvae.
Additionally, incorporating high-quality dried food options like flakes, micropellets, and granules is essential. Notably, these fish may also exhibit nibbling behaviour on algae and soft-leaved plants, indicating their preference for plant matter. As an added benefit, the occasional inclusion of vegetable treats in their diet can provide valuable nutrients for their overall well-being.
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