The objective of this work was to evaluate the percentage of hatching after cooling of pacu (Piaractus mesopotamicus) embryos at -8ºC for six hours, treated with cryoprotectant solutions, to obtain a cooling protocol for the specie. There were 2.400 embryos in post-gastrula stage development, in seven cryoprotectants solutions and control with three replicates, in completely randomized design. Ethylene glycol and honey-jelly were inappropriate. The substitution of 50% sucrose did not produce positive results. The combination of methanol (9%) and sucrose (17.5%) performed 69.2% of hatching and is recommended for cooling of pacu embryos at -8 ºC for six hours.
Piaractus mesopotamicus; cryoprotectant; fish embryos; cooling; hatching rate
