Ameca splendens

Ameca splendens

Advanced scientific guide to long‑term care, conservation breeding, and colony management.

Goodeidae • Goodeinae EN • Endangered (restricted range) Hard, mineral‑rich, cool water

Taxonomy & evolutionary context

Order: Cyprinodontiformes
Family: Goodeidae
Subfamily: Goodeinae
Species: Ameca splendens

Ameca splendens is a monotypic goodeid endemic to the upper Río Ameca basin in Jalisco, Mexico. Once widespread in its limited range, it has suffered severe habitat loss and is now considered extinct in much of its natural distribution, persisting largely through captive and reintroduced populations.

Native habitat & environmental physiology

Hydrology

  • Clear to slightly turbid streams and spring‑fed pools.
  • Moderate flow with well‑oxygenated water.
  • Rocky and gravel substrates with macrophytes and periphyton.

Water chemistry (wild)

  • pH 7.4–8.2; GH 12–22 dGH; KH 8–16 dKH.
  • Conductivity typically 500–800 µS/cm.
  • Temperature 20–25°C, with cooler nights and seasonal variation.

Anthropogenic impacts include water abstraction, pollution, and habitat modification. Captive conditions should emphasise high oxygenation, strong mineral content, and moderate flow to reflect the species’ rheophilic, spring‑influenced ecology.

Optimised captive water parameters

Parameter Target range Rationale
Temperature 20–23°C Reflects cool, spring‑influenced habitat; reduces chronic stress.
pH 7.4–8.1 Matches natural alkaline conditions.
GH 14–22 dGH Supports robust osmoregulation and bone development.
KH 8–14 dKH Provides buffering; prevents pH instability.
Dissolved oxygen > 7.5 mg/L Species is active and rheophilic; high DO is beneficial.
Flow Moderate–strong Encourages natural behaviour and conditioning.

Short‑term exposure to 24–25°C is tolerated, but sustained warm conditions increase aggression, reduce lifespan, and may compromise reproductive output.

Nutrition & digestive biology

Ameca splendens is an omnivore with a strong herbivorous/periphyton component. In the wild it grazes aufwuchs, filamentous algae, and small invertebrates. Captive diets should prioritise plant matter and fibre, with animal protein used primarily for conditioning.

Daily base diet

  • High‑quality spirulina or algae‑based flake.
  • Vegetable‑rich pellets (0.8–1.2 mm).
  • Algae wafers and blanched greens (spinach, courgette, kale).

Conditioning foods

  • Live daphnia and small crustaceans.
  • Frozen mosquito larvae and cyclops.
  • Newly hatched Artemia (1–2× per week).

Avoid

  • Heavy, daily bloodworm feeding (fatty liver risk).
  • Very high‑protein carnivore pellets as staples.
  • Starchy, low‑fibre flake diets.

Reproductive biology & breeding protocol

Key traits

  • Matrotrophic livebearer with trophotaenia.
  • Gestation ~55–65 days.
  • Broods typically 10–25 large fry.
  • Sexual maturity at ~4–6 months under optimal conditions.

Breeding setup

  • Colony tank 120–180 L.
  • Ratio ~1–2 males : 4–8 females.
  • Strong filtration and oxygenation; moderate–strong flow.
  • Rockwork, open swimming space, and dense planting combined.
Behavioural note: males are assertive and display vigorously; maintaining a larger group of females and ample space reduces harassment and stress.
Genetic management: maintain multiple lines where possible, avoid mixing unknown stocks, and track generations to minimise inbreeding and preserve locality‑linked traits.

Fry rearing protocol

0–48 hours

  • Fry are large and fully formed at birth.
  • No feeding required in first 24–48 hours.
  • Maintain excellent water quality and high oxygenation.

Days 3–14

  • Crushed spirulina flake and micro‑pellets 2–3× daily.
  • Baby brine shrimp 1–2× daily for rapid growth.
  • Daily 20–30% water changes with matched parameters.

Days 14–60

  • Introduce algae‑coated stones and vegetable matter.
  • Gradually transition to adult‑style omnivorous diet.
  • Maintain moderate flow and high DO for robust development.
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