Definition: Nieuwkoop and Faber stage 25; age 1 day, 3 hr 30 min at 22-24 Celsius; corresponding to the following external morphological criteria: Eyes protruding equally far or further laterally than gill-area. Gill-area grooved. Invagination of otic vesicle indicated by pigment spot. Beginning of fin formation. Length: 2.8 - 3.0 mm.