Tandanus tandanus has recently experienced widespread population declines in eastern Australia; with some southern populations facing the risk of extinction, the management and conservation of Queensland populations should be considered a priority. To assist in clarifying the influence of changes to the natural environment on the reproductive ecology of T. tandanus, we investigated their early life history using naturally fertilised eggs and larvae from a wild population. Tandanus tandanus eggs ranged in diameter from 2.6 to 4.0 mm throughout development, and preservation of eggs in ethanol caused significant shrinkage (mean 18.9%). Hatching occurred between four to seven days (mean 5.29 days; 15.7 - 28.0°C). Larvae collected from nests ranged in age and standard length from one day old (mean SL 5.1 mm) to 16 days old (mean SL 15.3 mm); and SL was successfully modelled as a function of age. Larvae are likely to actively disperse from their nest at approximately 16 days old, and reach juvenility soon thereafter. Daily otolith increment formation was validated up to 28 days post-hatch; and sagittal otoliths were successfully used to develop an age-length relationship for larvae. These results can assist researchers in estimating the timing of critical recruitment events, and investigating how the species early life history is influenced by environmental conditions.