Red Phantom Tetra
Megalamphodus sweglesi
A deep-red, disc-shaped gem with a prominent 'phantom' black spot. Highly schooling, but has a strict requirement: it needs unusually cool water (20-23°C) and will waste away if kept too hot.
Température de l’eau
20 - 25 °C
Valeur du pH
6 - 7.5
Type d'eau
Eau douce
Niveau dans le bac
Milieu
Taille adulte
4,5 cm
Volume minimal du bac
>= 60 L
Groupe minimal
>= 6
GH
2 - 15 dGH
KH
1 - 7 dKH
TDS
40 - 295 ppm
Conductivité
63 - 461 uS/cm
Description de l'espèce
Geographical Origin and Habitat: Endemic to the upper Orinoco River basin in Colombia. Inhabits clear, highly oxygenated, and relatively cool, shaded forest streams with moderate flow.
Taxonomy and Morphology: Hyphessobrycon genus (deep-bodied tetras). Reaches about 4 cm. Round, disk-like shape rather than a torpedo profile. Males possess a dramatically elongated dorsal fin resembling a ship's sail.
Social Behavior: Peaceful and strictly schooling. They occupy the middle/bottom of the tank in a tight group. Males perform stunning mock-battles, erecting their massive dorsal fins and circling each other to establish dominance, a completely harmless but beautiful display.
Coloration and Sexual Dimorphism: Semi-transparent body heavily washed in bright carmine/blood red. A distinctive, large round black spot sits squarely on the flank behind the gills. Males are intensely red with a towering, pointed dorsal fin. Females are plumper with a short, rounded dorsal fin tipped prominently in white.
Soins, reproduction et cohabitation
Aquarium Setup: Minimum 60-80 cm (24-30 inches). Demands a dark substrate and dense edge planting to feel secure. If kept in brightly lit, bare tanks over white gravel, their red completely washes out to a stressed, transparent pink. Floating plants are recommended to dim the light.
Diet and Feeding: Micro-omnivore. Happily takes high-quality color-enhancing micro-pellets (astaxanthin helps the red). Must be fed frozen daphnia or brine shrimp weekly to maintain optimal health and coloration.
Water Quality: THE CRITICAL FACTOR IS TEMPERATURE: This is a cool-water tropical fish. Ideal temps are 20-23°C (68-73°F). If kept at standard tropical temps (26°C+ / 79°F+), their metabolism burns out, they lose color, and quickly die from bacterial infections. Demands soft, slightly acidic water (pH 5.0-6.5) with high oxygenation.
Compatibility and Cohabitation: Do NOT keep with Discus, German Blue Rams, or Cardinal Tetras (the temperature needs are completely incompatible). Perfect tankmates are cool-water Corydoras (Panda, Paleatus) or Hillstream Loaches. Must be kept in schools of 8-10+; kept in small numbers, they will hide constantly.
Aquarium Breeding: Challenging. Requires a dedicated, pitch-black spawning tank with peat moss. Parents eat the eggs instantly if not removed. Eggs are highly photosensitive and will fungus if exposed to bright light.
Risks and Diseases: 1. Rapid death and wasting due to being kept in warm 'standard' tropical tanks (26°C+). 2. Complete color loss from stress, bright lights, or small school sizes.
Origine et répartition géographiques
Endemic to the upper Orinoco River basin in Colombia. Inhabits clear, highly oxygenated, and relatively cool, shaded forest streams with moderate flow.
Origine
Océans tropicaux et récifsAmazonie, Orénoque et Guyanes
Profil de poisson
- Tempérament
- Semi-aggressive
- The Megalamphodus sweglesi is renowned for its peaceful, albeit somewhat shy and timid, temperament. They are highly social fish that absolutely depend on the presence of a sizable school for their confidence and well-being. When kept in sufficient numbers, they exhibit a lively and inquisitive nature, gracefully exploring the aquarium. However, if kept alone or in very small groups, they will likely become withdrawn, pale, and prone to hiding constantly.
- Régime alimentaire
- Omnivore
- In its natural habitat, the Megalamphodus sweglesi is a micro-predator that primarily feeds on tiny invertebrates and zooplankton. In captivity, they eagerly accept a staple diet of high-quality crushed flakes and micro-pellets. To support their overall health and promote optimal development—such as their stunning translucent red body with a dark shoulder patch—their diet should be frequently supplemented with live or frozen foods like Daphnia and cyclops. A diverse nutritional profile is crucial for maintaining a robust immune system.
- Espérance de vie
- 3-5 years
- Taille adulte
- 4.5 cm
- Ratio des sexes
- School
- When establishing a school of Megalamphodus sweglesi, maintaining a relatively balanced mix of males and females is beneficial. Males generally exhibit a slimmer profile and often display their characteristic vibrant red coloration more intensely compared to the plumper females. Having slightly more females than males can help dissipate any minor intra-species sparring when males display for dominance. Ultimately, keeping a large enough overall group size is more critical than the exact sex ratio.
- Fréquence d'alimentation
- Twice daily
- For optimal health, the Megalamphodus sweglesi should be fed small portions two to three times a day. Only offer an amount of food that the school can completely consume within two minutes to prevent water fouling. Overfeeding is a common issue with small characins, so strict portion control must be maintained. This frequent, small-meal approach closely mimics their continuous foraging behavior in the wild.
- Charge biologique
- Low
- The Megalamphodus sweglesi contributes a very low bioload to the aquarium ecosystem due to its small size. This makes them highly suitable for densely planted nano tanks and community setups alike. Despite their low waste production, maintaining a strict schedule of weekly water changes is highly recommended. A standard, high-quality biological filtration system will easily process the minimal waste generated by a healthy school.
- Courant
- Stagnant
- The Megalamphodus sweglesi naturally inhabits slow-moving streams and flooded forest areas, meaning they prefer gentle water flow in the aquarium. Strong currents from overpowered filters can quickly exhaust these small fish and cause chronic stress. A sponge filter or a baffled hang-on-back filter is usually the most appropriate choice to provide oxygenation without turbulent flow. Providing dense clusters of aquatic plants will also give them tranquil resting spots.
- Risque de saut
- Yes
- Like many similarly sized characins, the Megalamphodus sweglesi presents a moderate jumping risk, especially when initially introduced or startled. A secure, tight-fitting aquarium lid or a glass canopy is absolutely essential to prevent accidental losses. Employing floating plants such as Salvinia or Amazon Frogbit can provide overhead cover, which significantly reduces their skittishness. Stable water parameters and a peaceful environment will also minimize this leaping behavior.
- Reproduction
- Oviparous
- Breeding the Megalamphodus sweglesi requires a separate, dimly lit breeding tank equipped with soft, slightly acidic water. They are typical egg-scatterers that exhibit no parental care whatsoever, and they will readily consume their own eggs if left in the breeding tank. Spawning typically occurs among fine-leaved plants, after which the adults must be immediately removed. The microscopic fry require infusoria or specialized liquid foods until they are large enough to eat freshly hatched brine shrimp.
- Compatibilité et compagnons
- Peaceful
- As a peaceful schooling species, the Megalamphodus sweglesi thrives when kept in a vibrant community aquarium. They require the security of a group, so maintaining them in schools of at least eight individuals is essential. Excellent tank mates include small rasboras, Corydoras catfish, and other equally peaceful characins. Aggressive, large, or excessively boisterous fish should be strictly avoided to prevent them from becoming stressed or preyed upon.
- Niveau dans le bac
- Middle
- The Megalamphodus sweglesi is an active swimmer that primarily occupies the mid to upper levels of the aquarium water column. They deeply appreciate having a large, open swimming space in the center of the tank to school properly. They will often dart around the middle strata during the day, occasionally diving to the substrate during feeding times. Tall background plants and floating vegetation help them feel secure in these preferred swimming zones.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 3,2 ± 0,37 se
- Résilience
- Élevée (moins de 15 mois)
- Singularité phylogénétique (PD50)
- 0.5002
- Relation bayésienne longueur-poids
- a = 0.01995, b = 3.01
- VulnérabilitéVulnérabilité faible (10 / 100)
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