Mass-marking fish larvae can facilitate studies exploring connectivity and dispersal patterns of early life history phase fishes. Maternal injections of enriched stable isotopes can provide a means of mass-marking fish larvae during the embryonic phase, because the enriched stable isotopes become incorporated into the larval otoliths (transgenerational marking). However, this is a recent technique that has seen limited development and application. We explored the efficacy of transgenerational marking in the Purple-spotted gudgeon (Mogurnda adspersa) and Eastern rainbowfish (Melanotaenia splendida), and through a meta-analysis, evaluated the effects of this technique on larval fish morphology and growth across a range of marine and freshwater fishes. Transgenerational marking was highly effective, enabling mass-marking of larvae produced by adult females for up to 6 months post-injection. Multiple unique markers could be produced, with minimal impacts on larvae morphology, survival and growth. Our meta-analysis revealed minimal effects on marked larvae, suggesting that this technique may be applied to explore dispersal and connectivity in aquatic ecosystems¹ .