The comparison of growth, survival rate and behavior of Oscar fish (Astronauts ocellatus) fries fed by Artemia urmiana, earthworm and beef heart supplemented diets

This study was conducted to evaluate the effect of different fresh feed supplemented to commercial diet on growth and survival of Oscar fish (Astronauts ocellatus) (initial weight: 1.58-1.70 g) during 60-day period. The husbandry environment consisted of glass aquariums appropriate to growth with a photoperiod cycle of 12 L: 12 D. The water temperature was kept at 28 ±1°C. 360 fries of Oscar (initial weight: 1.58-1.70g) were randomly distributed in four treatments with three replicate aquaria per treatment fed by different diets including: 1: commercial concentrate (crud protein: 46-54%, crud fat: 11–15 %, maximum moisture: 11 %), 2: commercial concentrate feed + chopped earthworm, 3: commercial concentrate feed + adult Artemia urmiana and 4: concentrate feed +choped beef heart. Daily feeding was performed at a rate of 3 % body weight. The results showed that Artemia, earthworm and beef heart used as additive feed to commercial concentrate diet significantly increased growth indices compared to the concentrate feed (control diet) (p<0.05). The lowest survival rate was related to the treatment fed by earth worm (70.53±2.67 %) (p<0.05), however, no significant difference was observed between treatments fed by Artemia, earthworm and commercial diet (p>0.05). The number of total bacteria, lactic acid bacteria, mesophyll bacteria and enterobacteriacea were higher in fish fed with earthworm compared to the other groups. Aggressive behavior (take out the eyes of other fish, tearing and biting the caudal fins of smaller fish) was observed in the group fed with earthworm. In conclusion, feeding with A. urmiana and beef heart additives is recommended for Oscar fish due to their highest survival rates and growth indices.