Fish Selection for Tank Culture and Feeding Systems

1. Fish Selection for Tank Culture and Feeding Systems Gary J. Burtle University of Georiga Animal & Dairy Science Tifton, GA gburtle@uga.edu 229-386-3364

2. Feeding Indoor Tanks • Absolutely need a complete feed • Also needs to be digestible • May supplement with natural food or vitamin-rich products • Feed every day, or multiple times/day • Use lighting to grow algae on tank sides

3. Some Food Items • Natural foods • Fly larvae, worms, brine shrimp, meal worms • Ground meat • Beef liver, egg yolk, shrimp, fish paste • Yeast • Brewers, specialty • Food waste - vegetable • Fertilizer – for greenwater or biofloc

4. Live Food Culture

5. Brine shrimp for small fish Aeration and a light source are required. Salt water to hatch cysts.

6. Artificial Feed for Small Fish Finfish Feed 50% protein, small particle, Zeigler

7. Tilapia Fingerlings in TankWith Clear Water

8. Tilapia Nutrient Requirements • 25 to 30% protein • Can use plant materials effectively • Fiber should be kept low • Fat should contain linoleic (n-6) fatty acids, about 1% of diet • A complete vitamin and mineral supplement is needed for tank culture

9. Bluegill Nutrition Notes • Natural diets contain about 20% plant material • Large zooplankton, insects and crustaceans make up most of the diet • Therefore, bluegill are carnivorous • A relatively high protein (35 to 40%) and high fat (10 to 15%) diet is recommended

10. Protein Fiber Vitamin C Other Vitamins Minerals Note: Stock at >8 catfish per cubic foot 28 to 36% > 4% 80 mg/kg Stable C Complete (12 items) P, Zn, Co, Cu, I, Se, Mg, Fe, Ca Catfish Nutrient Requirements

11. Potential Bluegill Diets

12. Bream Growth in Recirculating System, 200 days (7 months) 1/3 lb

13. Growth of Israeli Hybrid Tilapia(pounds over weeks) 1.3 pounds of gain In 200 days

14. Tilapia Feeding System • Green water or small pellet feed for first three months • Supplement with a 28% protein feed for final 3 months • Feed conversion is expected to be 1.5 pounds of feed per pound of fish and could be better

15. Hybrid Tilapia at 800/1200 gal

16. Green Water Culture

17. What is Green Water? • Usually a blue-green algae/water mixture • Needs open air or greenhouse environment • Nitrogen and phosphorus provided by feed or fertilization • Other systems (“green manure”) • Duckweed • Azola water fern

18. Tilapia in Green Water • Green water provides a basis for nutrition, usually for smaller stages of fish • Prepared feed is used to finish the fish later in the growing season • Feed quality and cost can be lowered by the presence of green water

19. System Requirements to use Green Water • Light from the sun or grow lights • Heat source for the water • Aerating system • Sediment collection system

20. Simple Culture Tank and Sludge Removal Tank

21. Partitioned System for Catfish/Shrimp and Tilapia Tilapia Area Catfish Area

22. Production from PAS • Tilapia in two 8 ft compartments of the system (0.33 acres) • Stocked at 400 to 800 per compartment • Resulted in about 1,000 pounds of Tilapia • Reduced aeration requirement and improved water quality for catfish/shrimp production (6,000 pounds of catfish) • Algae was reduced from >100 mg/L to about 50 mg/L by Tilapia (less blue-green)

23. Exposed Tilapia Tank with High Rate Aeration BIOFLOC PRODUCTION = BROWN WATER

24. What is Biofloc? • Each floc is held together in a loose matrix of mucus that is secreted by bacteria, • bound by filamentous microorganisms, • or held by electrostatic attraction. • also includes animals that are grazers of flocs, such as some zooplankton and nematodes. • NEEDS A HIGH RATE OF AERATION.

25. Bacteria, algae, protozoa

27. Bottom Line • Use green water to reduce cost • Stock the fish that you can sell at a good price • Use supplemental feeds to finish out the fish • Tilapia still are the best candidate for tank culture as food fish • But, less regulation of bluegill or catfish.