Nematobrycon palmeri – Emperor Tetra
Nematobrycon palmeri – Keizertetra
The fish species known as Nematobrycon palmeri is commonly called the Emperor Tetra. It belongs to the Characidae family, recognized for its diverse and colorful freshwater fish.
Nematobrycon palmeri was first described by the ichthyologist Carl H. Eigenmann in 1911. The genus name “Nematobrycon” is derived from Greek, where “nḗmatos” means “thread,” referring to the three thread-like lobes of the caudal fin. The second part, “brycon,” is a common element in the names of the family Characidae and comes from the Greek word “brýchō,” which means “to bite” or “to eat greedily.” This likely refers to the fish’s upper jaw, which is fully equipped with teeth.
The species name “palmeri” is named in honor of the person who discovered or introduced the fish to science, in this case, MG Palmer.
Synonym: Nematobrycon amphiloxus
Description
Appearance
The Emperor Tetra (Nematobrycon palmeri) has an elongated, laterally flattened body. Its head is dark brown to black, while the sides feature a prominent, broad black stripe that extends from the gill covers to the tail. Above and below this black stripe, the body displays a bluish-to-greenish hue, with a whitish belly and back. The fins are transparent to light-colored, occasionally with a slight dark tint at the edges. This fish can reach a maximum length of approximately 6 centimeters.
Sexual dimorphism
Males are typically larger and more brightly colored than females. The males possess longer, thread-like extensions on their caudal fin. One noticeable distinction is eye color: males have blue eyes, while females have green eyes. The behavioral differences between the sexes are most apparent during reproduction. Juveniles resemble adult fish but are smaller and less vividly colored.
Behavior and Temperament
Nematobrycon palmeri is a peaceful schooling fish that thrives best in groups of at least 8 to 10 individuals, allowing them to display their natural schooling behavior. They are not shy and typically swim in the middle levels of the aquarium, although they can also descend to the bottom when searching for food. It is essential to avoid keeping them with aggressive or overly active species.
Life expectancy
The life expectancy of Nematobrycon palmeri in the wild is not precisely known. However, in an aquarium setting, they can live for more than 7 years. Their maximum lifespan depends on factors such as water quality and tank mates.
Similar species
The Emperor Tetra closely resembles Inpaichthys kerri, also known as the Royal Tetra. However, the differences between these species are clearly noticeable. The Nematobrycon palmeri is significantly larger than the Inpaichthys kerri. Additionally, the Inpaichthys kerri has an adipose fin located on its back, just before the tail fin, while the Nematobrycon palmeri lacks this adipose fin.
Biotope and Natural Habitat of Nematobrycon palmeri
The Emperor Tetra is native to Colombia, specifically found in the basins of the Atrato and San Juan rivers in the western part of the country. These fish inhabit the tributaries and small streams that flow into these larger rivers, making them river fish by nature.
Their natural habitat includes small, slow-flowing streams and tributaries that are rich in aquatic plants and abundant vegetation. The banks of these bodies of water are often lined with trees and other riverine plants. The bottom is composed of a mixture of sand, mud, and organic matter.
There is limited specific information about their natural predators. Being small fish, they are likely to be preyed upon by larger fish and other predators in their environment. Additionally, they are micropredators themselves, feeding on small insects, worms, crustaceans, and other forms of zooplankton.
The Emperor Tetra inhabits a tropical climate characterized by relatively constant temperature and humidity. They tend to avoid large rivers, but due to seasonal flooding or droughts in their natural habitat, they may temporarily be found in the larger rivers of the Atrato and San Juan river basins.
Diet of Nematobrycon palmeri
Diet in the wild
In the wild, the Emperor Tetra is a micropredator that feeds on small insects, worms, crustaceans, and other zooplankton. Their diet will vary depending on the season and availability of food sources.
Diet in the aquarium
In the aquarium, the Emperor Tetra thrives on a varied diet that includes both dry food (such as flake and pellet food) as well as live and frozen options. Providing a diverse diet is essential for the fish’s health and vibrant coloration. A good base diet consists of high-quality flake or pellet food. Additionally, you can offer small live and frozen foods daily, such as Daphnia, Artemia, and mosquito larvae. Including green food, like spirulina, can also enhance their varied diet.
The Aquarium
Aquarium size and layout
For a group of 8-10 Emperor Tetras, an aquarium with a bottom of at least 80 centimeters in length is recommended. For a larger school, a considerably larger aquarium is needed to provide sufficient space and to prevent territorial conflicts.
The setup should include a combination of dense planting, floating plants, and hiding places, such as wood or rocks. This arrangement creates an environment resembling their natural habitat and provides the fish with security. A substrate of fine sand is ideal; avoid using sharp stones or gravel.
Water parameters
The ideal water conditions for Nematobrycon palmeri are a temperature between 23 and 27°C, a pH between 5.0 and 7.5, and a hardness between 18 and 215 ppm. Regular water changes are essential to maintain good water quality.
Compatibility with other fish
The Emperor Tetra is a peaceful fish that thrives when kept with other non-aggressive species of similar size. Suitable tankmates for the Emperor Tetra include small Corydoras species, smaller tetras like the Cardinal Tetra, and other small, peaceful bottom dwellers. It’s important to avoid housing this fish with larger, aggressive, or overly active fish, as these can stress or injure the Emperor Tetra.
Breeding aquarium and conditioning
Set up a separate, dark breeding tank to achieve the best breeding results. Maintain a slightly higher temperature, around 28°C. It is essential to include a spawning grid to prevent the parents from eating the eggs, as they are known to be egg predators. You can also use a substrate with hard artificial grass or a few layers of marbles, which allow the eggs to fall in between. Additionally, providing a large tuft of Java moss will create an ideal environment for them to lay their eggs, completing the setup.
Use a sponge filter to filter the water. This ensures that the newly hatched fry are not sucked up by a filter that is too powerful. The surface of a well-turned sponge filter also contains tiny organisms that the youngest fish can feed on.
Condition the parent fish with a varied diet with plenty of live and frozen food, such as Daphnia and Artemia. This will encourage the fish to get into good condition and promote reproduction. Breeding reports vary on the best results. Some get the best results by putting a few together. Others prefer to put a whole breeding group.
The Spawn
During spawning, the fish’s colors become more intense. Males display their most vibrant colors. The courtship ritual is described as a “ball dance.” In which the fish “dance” around each other. The eggs are laid between fine-leaved plants, such as Java moss. The spawning takes place in the morning. The eggs are laid in the open, not in a cave or other hidden place.
The number of eggs per clutch is not known precisely, but it is relatively small. The size of the eggs is estimated at 2 millimeters.
Raising the young Emperor Tetras
Emperor Tetra eggs typically hatch within 1 to 2 days. The fry begin to swim freely after 4 to 5 days. There is no parental care involved, as the adult fish are known to eat their own eggs if given the opportunity. Therefore, it is advisable to remove the parents after spawning. You can later reintroduce them to the main aquarium.
The first food consists of fine dust food and Artemia-nauplii. A well-filtered and clean aquarium with regular water changes is essential for a high survival rate.
Nematobrycon palmeri additional details
Below are some additional details about the Emperor Tetra that were not covered in the previous chapters:
- Confusion with other species: The Emperor Tetra is often confused with the Inpaichthys kerri (Purple Emperor Tetra) and Nematobrycon lacortei. A distinction can be made based on eye color (blue in males of N. Palmeri, green in females, red in males of N. lacortei), the presence of an adipose fin in Inpaichthys kerri , and the length of the caudal fin spurs. There is also debate over the status of Nematobrycon amphiloxus, which is considered by some to be a color morph of N. palmeri.
- Color variation: The color of the Emperor Tetra can vary depending on the light conditions in the aquarium. In bright light, the yellow color dominates, while in dim light the purple/blue hue is more noticeable. There is also a “black” variant, which may be a color morph.
- Aquarium trade: The Emperor Tetra has been available in the aquarium trade since 1960 and is relatively easy to keep. However, most specimens in the trade are offspring of captive-bred fish.
- Taxonomic history: The taxonomic classification of the Emperor Tetra and related species is complex and has been the subject of debate and revision. The status of N. amphiloxus as a separate species or subspecies of N. palmeri is still not fully clarified. The description of N. lacortei as a new species is relatively recent.
- Geographic distribution: The Emperor Tetra occurs in the Atrato and San Juan river basins in western Colombia, but its exact distribution and population size are not fully known. There may be mixing of different color morphs due to the construction of canals in the past.
Conclusion
The Emperor Tetra (Nematobrycon palmeri) is a relatively easy fish to keep, even for beginning aquarists, provided that a few basic requirements are met. A spacious tank with sufficient hiding places and a group of at least 8-10 specimens are essential for their well-being. A varied diet, good water quality and suitable tankmates contribute to their health and vibrancy.
A notable feature is its relative ease of breeding, although the parents should be removed from the breeding tank to prevent cannibalism. Confusion with other species, such as Nematobrycon lacortei and Inpaichthys kerri, emphasizes the importance of accurate identification. Overall, the Emperor Tetra is an attractive and relatively easy-care fish that can make a fine addition to a community aquarium.
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Author
John de Lange
Copyright images
Leo Nooij
John de Lange
