Condition factor and organosomatic indices of fish represent a
way of monitoring environmental factor influence on fish. The rainbow trout
(Oncorhynchus mykiss, Wal.) individuals that were used in the work originated
from different brood stock and different fish farms. Spawning was carried out on
five selected fish farms. After that, the breeding eggs were delivered in Klasnik
hatchery where the same environmental conditions were provided during
embryonic development and cultivation of all five groups of individuals. As a
conditioning factor in this work Fulton’s condition factor and coefficients of the
heart, liver and spleen were analyzed. In all individuals we determined the total
length, standard length and body mass. In total, fifty individuals, which were
divided into five groups form five brood stock, were analyzed. The results show
significantly different values for the condition factor and organosomatic indices
between some of the analyzed groups.