Normal table of postembryonic zebrafish development: Staging by externally visible anatomy of the living fish

TLDR

The zebrafish is a premier model organism but lacks a standardized system for staging postembryonic development. This study introduces a staging series based on externally visible traits observable by brightfield, vital staining, or epifluorescence. The authors characterize changes in swim bladder, fins, pigment pattern, scale formation, larval fin fold, and skeleton, define discrete milestones, assess size–age relationships, evaluate temperature and density effects, document histological processing impacts, and provide reference images and reporting guidelines. They demonstrate that size correlates more closely with developmental progress than age, and that size–development relationships vary with temperature and density while histological processing alters measured size. Developmental Dynamics 238:2975–3015, 2009; © 2009 Wiley‑Liss, Inc.

Abstract

Abstract The zebrafish is a premier model organism yet lacks a system for assigning postembryonic fish to developmental stages. To provide such a staging series, we describe postembryonic changes in several traits that are visible under brightfield illumination or through vital staining and epiflourescent illumination. These include the swim bladder, median and pelvic fins, pigment pattern, scale formation, larval fin fold, and skeleton. We further identify milestones for placing postembryonic fish into discrete stages. We relate these milestones to changes in size and age and show that size is a better indicator of developmental progress than is age. We also examine how relationships between size and developmental progress vary with temperature and density, and we document the effects of histological processing on size. To facilitate postembryonic staging, we provide images of reference individuals that have attained specific developmental milestones and are of defined sizes. Finally, we provide guidelines for reporting stages that provide information on both discrete and continuous changes in growth and development. Developmental Dynamics 238:2975–3015, 2009. © 2009 Wiley‐Liss, Inc.