In recent times we’ve been often addressed by fish farmers of commercial sites for advice about reducing risks associated with the acceptance and further acclimatization of our fry. So in this article we would like to tell you about the main aspects of adaptation of fry trout in fish-farms.
Before you bring the fry bought from us to your farm you should prepare nurse-ponds for fish to be accepted. We recommend you to choose the mesh size for a nursery net as follows: fry weighing 4-6 grams requires a net with 5mm mesh, fry weighing 8-12 grams – 8 mm, for fry weighing 12 grams and above a 10 mm net will do. The day before planting fry in ponds the net should be disinfected. For this purpose 40% formalin solution is most often used as it has detrimental effect on all kinds of bacteria and viruses and is most beneficial by price.
After you get fish on the farm it must first be poured through with clean water for 30 minutes to remove mucus and foam, then we recommend treating it with prophylactic preparetions. The most accessible are:
• 3% sodium chloride solution, exposure time – 30 min.
• 0.1%, formalin solution, exposure time – 15 min.
Once the treatment is completed, the pouring of clean water is continued until the water in the containers with fish and the water of the reservoir are of equal temperature, but not faster than 1.0-1.5C per hour.
After stocking ponds you can start feeding the fry the next day. To increase the organism resistance against pathogenic microorganisms we offer you the feeding scheme that we ourselves use.
1. Ascorbic acid 1-4 g per 1 kg of feed. Chicktonic - 2 ml per 1 kg of feed. Olin is a probiotic; bacteria it contains are in spores. To activate them you should for some time (about 3 days) sustain the preparation in conditions necessary for bacterial growth. To do this Olin is diluted in warm sugar water (30-40 C) at the rate of 0.5 g per 100 ml of water per 1 kg of feed. This mixture is added into the entire daily food allowance and fed during a day. The course is 7-10 days.
2. Solvimin selen – 1-2 g/kg of feed. Rybin A – 1-2 g/kg of feed (it needs not be activated because it contains vitamin C which breaks down quickly in water). The course lasts for 7-10 days.
3. Don – 2 g/kg of feed. Succinic acid – 0.5 g/kg of feed. The course lasts for 5-10 days.
All these mixtures are pre-diluted with water on the basis of 100 ml per 1 kg of feed and mixed in a daily dose of feed.
In conclusion we’d like to say that the key to successful growing of our fry is in:
1. The observance of optimum planting densities
2. Timely replacement of nets from smaller to larger ones for better water exchange in nurse-ponds
3. In order to avoid excessive variation in body weight you should give the fry feed of grain size corresponding to its weight scattering it throughout the whole nurse-pond area.
Good luck to you,
Fish-farmers of CJSC “Virta” Ekaterina Monina and Larisa Arzhanova.