Population growth, habitat destruction, climate change, and new diseases are all threats to the world's fisheries and aquaculture. Traditional selective breeding has achieved success, but has some drawbacks such as long breeding cycles, polygenetic nature of traits, and limited genetic diversity in closed populations. The potential of CRISPR-Cas genome editing is a recent technology that has been used in zebrafish since 2013, and is now revolutionizing the genetic improvement of Atlantic salmon, Nile tilapia, rainbow trout, channel catfish, grass carp, and others. This precision has been further improved by advanced technologies such as base editors, prime editors, CRISPRa, and CRISPRi. Applications include growth enhancement through myostatin disruption; increased disease resistance, reproductive efficiency, flesh quality and thermal/osmotic stress tolerance. These tackle key production bottlenecks, while contributing to lower use of antibiotics, lower environmental footprint and climate-resilient systems based on the UN SDGs. Even with these challenges, there are significant issues off-target effects, mosaicism, regulatory issues, public acceptance and polygenetic traits. Now, new technologies like artificial intelligence-driven design, multi-omics, multiplex editing, and epigenome editing provide answers. To be fully commercialised, regulatory harmonisation and transparent communication are paramount.