Home / Fishes / Killifish and livebearers / Butterfly splitfin
No federal permit to keepButterfly splitfin
Ameca splendens
Fishes › Killifish and livebearers (Cyprinodontiformes) › Goodeidae (Goodeid livebearers and killifish)
The butterfly splitfin or butterfly goodeid (Ameca splendens) is a bony fish from the monotypic genus Ameca of the splitfin family (Goodeidae).
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 3.1 in / 8 cm).
- Water: Freshwater.
- Temperature: 79–90°F (range recorded for this species).
- pH: 6–8.
- Hardness: 9–19 dGH.
- Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 35 × 12 in (roughly 21 US gallons); space needed is rated “large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, pH 7–8, 10–20 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Difficult (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “A densely planted aquarium with a dark substrate will allow it to exhibit its colours to the best effect.”
- Diet: “An omnivorous and greedy feeder, it will accept most foods offered.”
- Tankmates: “Not a good community fish as it can be quite aggressive, particularly the males.”
- Breeding: “An easily-bred live bearer.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Goodeid livebearers and killifish
Applies to most species in this group. Habitat: Goodeids occupy freshwater springs and their outflows, including Mexican splitfin habitats and isolated Nevada poolfish springs. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For Ameca splendens, provide at least 250 litres (66 US gallons); for Empetrichthys latos, at least 150 litres (40 US gallons), favouring broad tanks over height.
- Provide roots, rocks and dense vegetation patches that interrupt sightlines while leaving swimming space.
- Provide moderate to swift circulation; Ameca requires strongly oxygenated water, with the working group recommending at least 8 mg/L dissolved oxygen.
- The working group recommends weekly 60–80% water changes for these spring-associated species; match replacement chemistry and temperature carefully.
- Keep species and documented populations separately to preserve conservation stock identity.
Diet
- Algae and aufwuchs, especially for Ameca
- Vegetable supplements and plant-rich foods for Ameca
- Quality flakes, granules or tablets
- Artemia
- Daphnia or mysids, particularly for Empetrichthys
Social life
- Maintain breeding colonies with cover and room for subordinates; Ameca males can fight and nip other fishes. Fry are often tolerated when shelter and feeding are adequate.
Health watch
- Reduced disease resistance and accelerated ageing in Ameca kept persistently warm with inadequate water renewal
- Aggression-related fin damage
- General aquarium-fish water-quality disease and malnutrition; family-specific prevalence is not established
Understanding the animal
About this animal
About this animal
It was formerly found throughout the Ameca River drainage in Mexico; the type locality is Rio Teuchitlán in the vicinity of Teuchitlán, Jalisco, near the town of Ameca. The species was historically only found in an area about 10 miles (15 km) in diameter but in the early 21st century, searches have found it in a few other locations in the region, up to 100 km away at Cuyacapán.
Quoted from the Wikipedia article “Butterfly splitfin” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater. Stays near the bottom. Raised commercially in Florida, U.S.A. |
| Water it lives in | Freshwater, 79–90 °F (26–32 °C), pH 6–8, hardness 9–19 dH. |
| Climate | Tropical climate. |
| Behavior to plan for | Breeding: internal live bearers. |
What this means for care
- Keep water within its wild range, 79–90 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 93°F (up to 100°F in the hottest sampled areas) |
| Cool-season lows | about 43°F (down to 29°F in the coldest sampled areas) |
| Average temperature | 58–70°F across sampled records |
| Relative humidity | 54–61% on average (driest month about 42%) |
| Rainfall | about 829 mm a year, with strong wet and dry seasons |
Measured at 7 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | The butterfly splitfin or butterfly goodeid (Ameca splendens) is a bony fish from the monotypic genus Ameca of the splitfin family (Goodeidae). It was formerly found throughout the Ameca River drainage in Mexico; the type locality is Rio Teuchitlán in the vicinity of Teuchitlán, Jalisco, near the town of Ameca. The species was historically only found in an area about 10 miles (15 km) in diameter but in the early 21st century, searches have found it in a few other locations in the region, up to 100 km away at Cuyacapán. Today, the species is rated as critically endangered by the IUCN. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Appearance and size | Maximum length 8.0 cm tl male/unsexed. — FishBase |
| Biology | Migratory behaviour is undetermined. Raised commercially in Florida, U.S.A. — FishBase |
| History and naming | The butterfly splitfin is placed in the monotypic genus Ameca. Phylogenic research by Shane Webb showed that its closest relative is the jeweled splitfin Xenotoca variata, the type species of genus Xenotoca, which is actually more closely related to the butterfly splitfin than it is to the other species assigned to Xenotoca. — Wikipedia (community-edited) |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 35 × 12 in (about 21 US gallons).
Veterinary & husbandry research
Veterinary & husbandry research
- Elaphoidella grandidieri (Harpacticoida: Copepoda): demographic characteristics and possible use as live prey in aquaculture Nandini S et al., Journal of environmental biology 2011
- Beyond the point of no return? A comparison of genetic diversity in captive and wild populations of two nearly extinct species of Goodeid fish reveals that one is inbred in the wild Bailey NW et al., Heredity 2007
Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. 170
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Goodeid Working Group: Ameca splendens Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Goodeid Working Group: Empetrichthys latos Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Goodeid Working Group: Objectives Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
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