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FishFreshwaterIntermediate
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Butterfly goodeid
Ameca splendens
A Mexican livebearer critically endangered in the wild: today it survives almost exclusively through hobbyist conservation programs. Adult males display metallic scales with a distinctive black and yellow crescent on the tail. A tireless swimmer and voracious algae eater, it is one of the few species that actively consumes cyanobacteria. Its reproduction is unique in the fish world: fry develop attached to the mother via an umbilical-like structure called the trophotaenia, which falls off shortly after birth.
Class:Actinopteri
Order:Cyprinodontiformes
Family:Goodeidae
Genus:Ameca
Species:Ameca splendens
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Water Temperature
22 - 30 °C
pH Value
7 - 8.5
Water type
Freshwater
Adult size
12 cm
Minimum tank volume
>= 150 L
Minimum group
>= 8
GH
10 - 25 dGH
KH
5 - 12 dKH
TDS
200 - 495 ppm
Conductivity
313 - 773 uS/cm
Species description
Geographical Origin and Habitat: Endemic to Mexico, once abundant in the Ameca river basin. It now survives in the wild only in small isolated springs (hot and strongly alkaline biotopes) being on the brink of extinction in its original habitat (Critically Endangered).
Taxonomy and Morphology: Family of the Goodeids (Goodeidae). Stocky fish, very high on the back, equipped with massive fins and a slightly superior mouth. Reaches 8 cm (3 inches) for females and about 6-7 cm for males.
Social Behavior: Marked gregariousness with a hierarchical and pugnacious temperament. They are not fish for quiet communities: they are restless, intrusive and manifest the odious habit of biting fins ("fin-nipping") to any slow tankmate.
Coloration and Sexual Dimorphism: Chromatically splendid males: flanks of a metallic shine with emerald green reflections, interrupted by black spots, with a flashy and wide bright golden-yellow band bordered with black that adorns the caudal fin. Females uniformly olive-gray with black spotting all over the body.
Care, breeding and tankmates
Aquarium Setup: Tank starting from 100 liters (25 gallons), dedicated to a single school (species-tank). Calcareous rocks to guarantee hardness and filamentous algae or mosses. Given the aptitude to graze continuously, they will destroy soft-leaved plants; prefer Java ferns and Anubias.
Diet and Feeding: In nature they are formidable algae grazers. In the aquarium they will clean every surface of filamentous and brush algae. The diet must be 70% vegetable (spirulina flakes, boiled spinach). Too much protein rapidly leads to fatty degeneration of the liver.
Water Quality: Unrivaled robustness but requires rock-hard waters. pH 7.5 - 8.5, GH from 10 up to over 25, with tolerance for warm temperatures (22-30°C / 72-86°F). The collapse of the pH or soft and acidic waters are lethal in a short time.
Compatibility and Cohabitation: Categorically discard slow or long-finned fish (Guppies, Bettas, Angelfish), which would be skinned alive. If absolutely necessary, pair only with armored Central American rock cichlids or very fast large cyprinids. Better monospecific tank.
Aquarium Breeding: True viviparous (not ovoviviparous). The embryos are nourished directly by the mother through structures similar to an umbilical cord (trophotaeniae). Gestation lasts about 6-8 weeks and the pups (10-30) are born giant (almost 2 cm) and perfectly independent.
Risks and Diseases: Keeping and reproducing this species in the aquarium is a project of pure conservation, given the desperate situation in nature. They are subject to external parasitosis (Ich) if kept in too soft waters. Require vigorous oxygenation.
Geographic Origin and Distribution
Endemic to Mexico, once abundant in the Ameca river basin. It now survives in the wild only in small isolated springs (hot and strongly alkaline biotopes) being on the brink of extinction in its original habitat (Critically Endangered).
Origin
Extra-Amazon South AmericaCentral America and Caribbean
Fish profile
- Temperament
- No verified data available
- Diet
- No verified data available
- Life expectancy
- No verified data available
- Adult size
- 12 cm
- Sex ratio
- No verified data available
- Feeding frequency
- No verified data available
- Bioload
- Medium
- Flow
- No verified data available
- Jump risk
- No verified data available
- Reproduction
- No verified data available
- Compatibility & tankmates
- No verified data available
- Tank level
- No verified data available
The catalog's scalar value is 12 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 12 cm for this species, recorded as total length (TL). The taxonomic record consulted is Ameca splendens (v25.04); female 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.
The single-adult profile is classified as medium bioload. The bioload-v2 rubric deterministically assigns this class from the verified maximum length of 12 cm; it is a catalog management category, not a direct measurement of waste output.
Window to the official scientific data of the species
Data synced on: 06/15/2026
Scientific Parameters & Models
- Trophic level
- 2 ± 0.1 se
- Phylogenetic uniqueness (PD50)
- 1
- Bayesian Length-Weight
- a = 0.01202, 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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Recommendations grouped by close relatives, companion choices, and similar care.
