In the previous decade, four species of non‐native goby have invaded the middle section of the River Danube. To understand the problems associated with these invasions better, we examined the external morphology of 184 round goby Neogobius melanostomus specimens using both triple regression (distance‐based measurements) and geometrical (coordinates‐based measurements) analysis within an ontogenetical and epigenetical aspect. Using geometrical analysis of distance‐based characters, we found that the external body shape in four size groups of round goby remained essentially unchanged. Such direct development represents a strongly precocial (i.e. specialized) life‐history, whereas earlier maturation in this non‐native population suggests a shift back towards more altricial (i.e. less specialized, more generalized) life history. This combination of altricial–precocial trajectories seems to be typical for invasive round gobies and may be one of key factors for their successful colonization of new environments.