The Lichtman laboratory and Engert laboratory at Harvard University, in collaboration with the Connectomics team at Google, are releasing the Fish1 dataset and its companion paper. Fish1 is the comprehensive whole-brain connectomics dataset for the 7-day post-fertilization (7dpf) larval zebrafish, combining electron microscopy (EM) and confocal light microscopy (LM) from the same specimen.

The resulting EM dataset, acquired at a resolution of 4 nm × 4 nm × 30 nm, provides ultrastructural details such as synaptic connections and subcellular features. This volume includes 187,053 cell bodies encompassing the zebrafish brain, spinal cord and ganglia, with 26,915 vglut2a-positive and 14,510 gad1b-positive cells. The dataset is editable through a collaborative proofreading tool, CAVE, allowing the community to reconstruct neurons of interest, analyze their connectivity, and overlay neurotransmitter information to test their circuit models.

• Paper — manuscript, abstract, and Neuroglancer states from the accompanying publication.
• Gallery — visual overview of the dataset.
• Proofreading — manual reconstruction using CAVE (Connectome Annotation Versioning Engine). Browsing requires a Google account; to request editing privileges please fill out this form.
• Programmatic Access — Python client tutorials for querying neurons, synapses, and skeletons.
• VAST — voxel annotation tool and dataset file downloads.
• FishExplorer — anatomical atlas integration for cross-fish comparative analysis.
• Data Policy — publication, authorship, and collaborative coordination guidelines.