Summary This study determined the effect of two different activating solutions (‘Woynarovich’ and ‘Billard’) on the effectiveness of controlled insemination of eggs of the Eurasian perch, Perca fluviatilis L., compared to hatchery water. Moreover, the study established the period during which such eggs can be fertilised in each of these media. The experiments were conducted on eggs obtained by induced spawning of wild perch females, stimulated hormonally with HCG (500 IU kg−1). The eggs were divided into samples with about 200 eggs in each, which were activated with each of the test media. Subsequently, semen (0.05 mL) was added to each sample after 15, 30, 45, 60, 90, 120, 150 and 180 s following egg activation. The results were compared to a control group [semen was added to an egg sample before activation (0 s)]. Moreover, the sperm motility parameters and the time of sperm movement in each of the tested activating liquids were analysed. The results indicated that perch eggs activated with hatchery water remain capable of fertilisation for 150 s. The lowest survival rate of embryos was found in the control group, which could be attributed to the shortest motility time of spermatozoa (maximum 37 s) when activated with hatchery water. A similar time of egg fertilisation ability was recorded following the use of Billard solution (150 s), whereas eggs treated with Woynarovich solution remained capable of fertilisation throughout the experimental test period (180 s). The percentage of fertilisation was highest (P < 0.05) in that group (at least 88% of live embryos were observed at the eyed-egg stage). The results indicated that Woynarovich solution (4 g of NaCl and 3 g of urea in 1 L of water) proved to be the most effective medium for controlled insemination of perch eggs. On the other hand, when clean hatchery water was used to activate eggs, semen should be added to water after several seconds, which may significantly improve the fertilisation rate in controlled insemination trials.