As many aquatic species vital to ecosystem function and food production continue to decline, techniques to rescue dwindling populations and protect remaining genetic diversity are crucial. Genetic banking via cryopreservation may provide an avenue to catalog and stockpile a multitude of aquatic species. Cryopreservation is the process of cooling biological material (e.g., cells, tissues, ova, sperm, embryos, etc.) for storage in subzero or freezing temperatures. Low temperature storage reduces the biological and chemical reactions in living cells but can also promote damaging intracellular ice formation. Cryopreservation strategies use permeating (i.e., ice reducing) and non-permeating (i.e., dehydrating) cryoprotective agents (CPA) to stem chilling induced damage and reduce ice crystal formation. However, permeating CPA is often toxic and non-permeating CPA can induce damage via osmotic dehydration, making development of successful cryopreservation protocols challenging. Overcoming these challenges is critical for the successful cryopreservation of aquatic embryos or larvae and could help provide long term protection for threatened species and an insurance policy for future generations to restore and reintroduce genetically diverse representatives from critically important populations. Preservation of diploid aquatic embryos or larvae (i.e., aquatic seed - capable of developing into mature organisms) provides advantages over other haploid germplasm (e.g., sperm & oocytes) because it preserves genetic material from both parents. Genetic banking of plant cells, tissues, seeds, and mammalian embryos is common practice in agriculture and farming for selective breeding purposes, in case of disease outbreak or environmental catastrophe. However, genetic banking of aquatic seeds is nearly nonexistent to date with only a small number of successful embryo and larval cryopreservation protocols for invertebrate species such as oysters, clams, urchins, and mussels. The relatively large size (i.e., low surface area: volume ratio), multiple membrane bound compartments (i.e., yolk, blastoderm, perivitelline space, chorion), high yolk content, and chilling sensitivity of aquatic seeds make them extremely difficult to cryopreserve. Recent advancements in rapid cooling for storage in liquid nitrogen (-196°C) and ultra-rapid laser rewarming (>107 °C/min) have led to major breakthroughs and new opportunities in cryopreservation for aquatic germplasm. Successful aquatic seed cryopreservation provides an opportunity for 1) immediate culture of embryos or larvae for aquaculture broodstock replenishment, 2) improvement of restocking hatchery systems, 3) reintroduction of locally extirpated wild populations, and 4) alleviating pressures on wild caught populations.