Medaka provides accessible eggs and diverse genetic lines, but taxonomy, density, diet and environment must be reported whenever its phenotypes are interpreted.
The axolotl connects regeneration, a giant genome and genetic tools, but its scientific value depends on rigorous lineage identity and husbandry records.
Night monitoring reveals rest, aggression and hidden space use. In public aquariums it strengthens daytime welfare checks but cannot diagnose disease alone.
Zebrafish enrichment is an environmental variable to test: behavioural benefit, hygiene, stocking density and reproducibility must be assessed together.
Fish parasites can strengthen pollution monitoring when host ecology, parasite life cycles, chemical matrices and seasonal variation are analysed together.
Reliable shark and ray diets combine suitable prey, individual delivery and longitudinal records rather than relying on one universal feeding percentage.
