FishFreshwaterIntermediate
©AI Generated·Proprietary
Green Line Lizard Tetra
Iguanodectes spilurus
Elongated, pencil-like tetra featuring a brilliant neon green horizontal stripe. Rapid surface swimmer that requires a tightly covered, long aquarium.
- Taxonomy
- Class:ActinopteriOrder:CharaciformesFamily:IguanodectidaeGenus:IguanodectesSpecies:Iguanodectes spilurus
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Water Temperature
23 - 27 °C
pH Value
6 - 7.5
Water type
Freshwater
Tank level
Surface and middle
Adult size
10 cm
Minimum tank volume
>= 100 L
Minimum group
>= 1
GH
2 - 15 dGH
KH
1 - 7 dKH
TDS
40 - 295 ppm
Conductivity
63 - 461 uS/cm
Species description
Geographical Origin and Habitat: Widespread across the Amazon, Orinoco, and Essequibo basins. Lives exclusively in the upper levels of slow to moderately flowing forest streams, often holding position under floating vegetation.
Taxonomy and Morphology: Highly aberrant Characin shape (10 cm). Looks like a cross between a pencilfish and a small pike: extremely elongated, cylindrical, hydrodynamic body. Mouth features multicuspid teeth for grazing plant matter or fallen insects.
Social Behavior: Schooling fish (minimum 6-8). Stays in the upper half of the tank. Extremely fast and darting swimmer. Males perform stunning parallel fin-flaring displays. Peaceful to everyone, but becomes neurotic and glass-surfs in tanks that are too short.
Coloration and Sexual Dimorphism: Silver-olive base, sliced horizontally by a brilliant, razor-thin neon green stripe, sometimes bordered by pale red/orange. Small black spot at the tail base. Males develop reddish anal/pelvic fins and microscopic mating hooks.
Care, breeding and tankmates
Aquarium Setup: Demands LENGTH. A school needs a 100-120+ cm long tank due to their explosive surface acceleration. TIGHT LID IS MANDATORY: they are phenomenal jumpers and will escape through tiny gaps. Floating plants (Frogbit) to dim the light and provide overhead security are highly recommended.
Diet and Feeding: Omnivore with strong Herbivorous tendencies. In nature, they eat a lot of algae and plant matter. Will eat floating flakes/pellets, but MUST be given a green component (Spirulina, blanched veg) or they will shred soft aquarium plants or duckweed.
Water Quality: Adaptable but requires clean water. Prefers acidic to neutral water: pH 5.5-7.0 (tolerates up to 7.5). Soft to medium hardness. 23-27°C. Keep nitrates low.
Compatibility and Cohabitation: Perfect, unusual dither fish for Amazonian communities (Corydoras, Apistogramma, Plecos). Unfit for large cichlids (Angelfish, Discus) which will view their cylindrical bodies as perfect prey.
Aquarium Breeding: Rare in home aquaria. Egg-scatterers in fine-leaved plants. Requires very soft/acidic water and immediate removal of parents.
Risks and Diseases: 1. Jumping to their death (the #1 cause of loss). 2. Fatal snout injuries from crashing into the glass when spooked in small tanks. 3. Constipation/bloat if fed an all-meat diet without greens.
Geographic Origin and Distribution
Widespread across the Amazon, Orinoco, and Essequibo basins. Lives exclusively in the upper levels of slow to moderately flowing forest streams, often holding position under floating vegetation.
Origin
Cosmopolitan or introducedAmazon, Orinoco, and GuianasNorth America
Fish profile
- Temperament
- Semi-aggressive
- They are a timid, peaceful, and obligate schooling species. They must be kept in groups of at least eight individuals; more is always better. Without a school, they will suffer immense stress and hide away until they perish.
- Diet
- Omnivore
- They are omnivorous micro-predators that feed on small insects and zooplankton in the wild. In the aquarium, they readily take crushed flakes, micro-pellets, and frozen baby brine shrimp. High-quality dry foods supplemented with frozen foods will keep them thriving.
- Life expectancy
- 3-5 years
- This unusual characin typically lives between 3 and 5 years in captivity if kept under proper conditions. The longevity of the fish is positively influenced by consistent water cleanliness and a varied, balanced diet. It is essential to prevent sudden chemical changes in the tank, which can weaken its immune system and reduce its life expectancy.
- Adult size
- 10 cm
- The catalog's scalar value is 10 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 10.15 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Iguanodectes spilurus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Group
- Males are slimmer and often display slightly more vivid coloration along their lateral line. Females are noticeably rounder, especially when they are carrying eggs. They are best kept in a mixed-sex group to encourage natural displays.
- Feeding frequency
- Twice daily
- Feed them tiny amounts once or twice a day, ensuring they consume it all within two minutes. They primarily feed from the water column, so slowly sinking foods are best. Take care not to overfeed, as uneaten food will spoil the water.
- Bioload
- They produce a very low bioload, appropriate for their slender build and small size. Routine water changes and standard filtration easily handle their metabolic waste. They thrive in mature tanks where water parameters are highly stable.
- Flow
- Stagnant
- They prefer moderate water flow that mimics the constant current of their natural streams. This flow encourages healthy exercise and tighter schooling. However, ensure there are areas of lower flow where they can rest at night.
- Reproduction
- Oviparous
- Breeding occurs in soft, acidic water among fine-leaved plants or artificial spawning mops. They are egg scatterers and offer no parental care whatsoever. Adults will eagerly eat the eggs, so they must be removed right after spawning.
- Compatibility & tankmates
- This species is exceptionally peaceful and ideal for any calm community aquarium. They do well alongside small rasboras, corydoras, and other tranquil tetras. Never house them with large, boisterous, or predatory fish.
- Tank level
- Top/Middle
- They navigate the middle to upper levels of the water column almost exclusively. Provide plenty of unobstructed horizontal swimming space. Perimeter planting is ideal to provide cover without impeding their swimming lines.
Scientific Parameters & Models
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3.3 ± 0.4 se
- Phylogenetic uniqueness (PD50)
- 0.5039
- Bayesian Length-Weight
- a = 0.01072, b = 3.01
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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