Medaka feeding | Aquapedia

Evidence-backed findings

A controlled husbandry study found that dietary restriction materially affected medaka growth and reproduction. Fish fed around 3–4% body weight/day showed slower somatic growth than fish fed to excess, and stocking density plus photoperiod also affected egg production and maturation. This supports treating feeding amount as a measurable husbandry variable rather than a fixed ornamental-fish rule.

A 2022 controlled comparison tested three feeding regimes in medaka from 1–6 months. The center's custom regime (commercial flake food + beef-liver paste + live brine shrimp) produced larger fish, higher survival and higher fecundity than Gemma or the laboratory-defined WAT regime. The authors concluded that zebrafish-oriented diets are not automatically optimal for medaka and species-specific regimes are needed.

Claim class: EVIDENCE-BACKED for the tested regimes; not a universal recommendation to feed beef liver.

Next evidence queue

1. Controlled medaka protein/lipid requirement studies with explicit diet composition.

2. Temperature-dependent food intake and seasonal feeding evidence.

3. Comparative larval trials: Artemia vs rotifers/paramecia/microdiets.

Additional evidence added 2026-09-08

A 2024 Oikos methods/background synthesis describes Oryzias latipes as omnivorous, feeding mainly on zooplankton while also taking diatoms, algae and aquatic insects, citing earlier ecological work. This supports a species-level omnivore/micro-predator profile rather than a purely insectivorous or purely herbivorous label.

Claim class: STRONG SCIENTIFIC SECONDARY pending retrieval of the cited primary diet studies.

A 2025 controlled study found that long-day breeding condition increased food intake in female medaka relative to non-breeding short-day condition, while the same difference was not significant in males. The work links this response to ovarian estrogenic signaling and AgRP1. This directly supports adjusting feeding expectations during active female reproductive condition instead of prescribing an invariant year-round amount.

Evidence expansion — late 2025/2026 digestion and diet-risk literature

A 2025/2026 comparative knockout study found that loss of try (trypsin) impaired digestion, growth and intestinal development in Japanese medaka larvae; 15-dph knockout larvae had reduced intestinal villus height and body length. Adult knockout fish also showed reduced size plus liver/intestine pathology and altered intestinal-microbe diversity. amy (amylase) loss produced a substantially milder digestion phenotype in the reported comparisons.

Claim class: EVIDENCE-BACKED / DIGESTIVE-PHYSIOLOGY CONTEXT. This supports protein-digestion adequacy as biologically important, but does not by itself establish an ornamental-feed crude-protein optimum.

A controlled medaka model fed a high-fat diet from the hatching stage for six weeks, followed by eight weeks of normal chow, found both reversible and persistent DNA-methylation changes into adulthood. This is disease-model evidence rather than a normal hobby feeding trial, but it strengthens the caution against treating chronically energy-dense/high-fat juvenile feeding as automatically beneficial.

Append — Otohime manufacturer primary + purified-diet citation — 2026-09-18

Recovered manufacturer/distributor particle-size ladder and B-1/B-2 proximate analysis in medaka-feeding-otohime-primary-2026-09-18.md. Claim class remains MANUFACTURER/DISTRIBUTOR PRODUCT RECORD; not Medaka-controlled outcome evidence and not a best-brand ranking.

The already-recorded purified vs flake/Artemia comparison is DeKoven et al. (1992), Laboratory Animal Science 42(2):180–189 (OSTI/PubMed record summarizing a casein-based purified diet adequate through reproductive maturity vs inadequate flake-only). Claim class unchanged: EVIDENCE-BACKED that complete formulation matters; not an ornamental crude-protein optimum.

Source pin: ; PubMed abstract family via DeKoven purified diet medaka 1992.

Public research references

Listed research leads are not automatically supporting evidence for every individual claim.