Comparative Assessment of Diet-Induced Growth, Reproductive Output, and Carotenoid Pigmentation in Four Ornamental Fish Species under Home Breeder-Tank Conditions: A 12-Month Latin-Square Crossover Trial

Abstract

Evidence-based feeding protocols for the home breeder-tank scale that dominates Indian ornamental fish production are largely absent from the literature. The present twelve-month investigation (January–December 2025) evaluated four practical diets — a commercial flake control (Diet A), an Artemia-enriched diet with astaxanthin at 150 mg kg−1 (Diet B), a Tubifex-enriched diet using locally collected oligochaetes (Diet C), and a laboratory-formulated cold-pressed pellet (Diet D) — on growth, reproductive output and carotenoid pigmentation of four commercially important species: the banded gourami Trichogaster fasciata, the goldfish Carassius auratus, the guppy Poecilia reticulata and the molly Poecilia sphenops. A 4 × 4 Latin-square crossover design was implemented (four 54-L home aquaria, five fish per species; n = 20 fish total). Mixed-effects modelling revealed a significant main effect of diet on SGR (F3,45 = 22.6, P < 0.001) and FCR (F3,45 = 18.4, P < 0.001), and a significant species × diet interaction (P < 0.01). Diet C maximised growth in T. fasciata and P. reticulata, whereas Diet B was optimal for C. auratus and P. sphenops. Diet B produced the highest muscle carotenoid concentration (mean 18.0 ± 3.0 µg g−1), coloration score (8.0 ± 0.5 / 10) and marketability across all species. Reproductive output peaked uniformly in May–July. We propose an integrated rotational feeding framework — Diet C for growth and Diet B for reproduction and pigmentation — applicable to home breeder-tank units of Muzaffarpur and analogous Indo-Gangetic plain districts.