V. Krasteva*, A. Zaikov, M. Yankova
Institute of Fisheries and Aquaculture, 4003 Plovdiv, Bulgaria
(Manuscript received 20 June 2019; accepted for publication 1 December 2019)
Abstract. The present study investigated the growth performance, weight gain, feed conversion ratio, growth and survival rate of European catfish (Silurus glanis L.) fingerlings reared for one month in tanks with different colours. Four colours were used: light blue, white, green and black. The experimental unit was a flow-through system (0.8 L.min-1) consisting of eight tanks with water volume of 30L, continuous air supply and water heaters. Two hundred fish with an average weight of 1.85±0.62g were stocked in each tank. Results from the study demonstrated that the weight gain and the feed conversion ratio were poorly affected by the tested tank colours. Weight gain is slightly higher in groups A (blue) and B (white) than in groups C (green) and D (black). However, no significant difference was found in terms of weight gain among the experimental groups (p>0.05). Survival rate was the highest in group C (91%) followed by group D (88.5%). Thus, for rearing of European catfish fingerlings it is preferable to use dark coloured tanks, which resemble the natural habitat of the fish.