Despite tremendous progress in understanding the nature of the immune system, the full diversity of an organism’s antibody repertoire is unknown. We used high-throughput sequencing of the variable domain of the antibody heavy chain from 14 zebrafish to analyze VDJ usage and antibody sequence. Zebrafish were found to use between 50 and 86% of all possible VDJ combinations and shared a similar frequency distribution, with some correlation of VDJ patterns between individuals. Zebrafish antibodies retained a few thousand unique heavy chains that also exhibited a shared frequency distribution. We found evidence of convergence, in which different individuals made the same antibody. This approach provides insight into the breadth of the expressed antibody repertoire and immunological diversity at the level of an individual organism.