The onset of active gill respiration in post-embryonic zebrafish (Danio rerio) larvae triggers an increased sensitivity to neurotoxic compounds

•Regarding lethality, early, gill breathing, postembryonic zebrafish represented the most sensitive life stage after exposure to neurotoxicants, compared to both embryos and adult fish.•Switch from cutaneous to gill respiration during development of zebrafish and upcoming respiratory failure might be the reason for increased sensitivity to neurotoxic substances.•Swimbladder deflation in early gill breathing stages of zebrafish may be indicative for the respiratory failure syndrome (RFS).•Intermediate storage of (lipophilic) substances in the yolk of zebrafish embryos may contribute to minor sensitivity to neurotoxic compounds in these life stages.