Wong TT, Zohar Y. Production of reproductively sterile fish by a non-transgenic gene silencing technology. Sci Rep. 2015 Oct 29;5:15822. doi: 10.1038/srep15822.
This group bathed zebrafish embryos (with chorion intact) in Vivo-Morpholino solutions, with oligos targeting dead-end (dnd).
"Optimal conditions were achieved when embryos, immediately after fertilization, were immersed with dnd-MO-Vivo at the initial concentration of either 60 or 40 μM followed by a lower serially diluted concentration. Under these conditions, 100% induced sterility was achieved even when the total immersion time was reduced from 24 to 5 hours. In 8 independent experiments, 736 adults developed from these conditions were all found to be infertile fish that possessed minimally-developed gonads that lacked any gametes."
This appears to be a generally-applicable approach to easily generating batches of adult fish that underwent transient gene knockdown as embryos.