PANGASIUS EXTENSIVE FARMING GUIDLINE

  I/ Technical parameters of farming pond

- Water level in pond has to reach at least 2m before seeding.

- Water level in pond has to reach at least 3m when fish is from the weight of 500g.

- Pond parameters:

+ pH: 6,8 – 7,5.  ( Its deviation is not allowed to be over 0.5 within a day )

+ O₂:  > 3 mg/l

+ NH₃: < 0,1 mg/l

+ H₂S: < 0.03 mg/l

+ Salinity: < 3%₀

 

II/ Farming pond preparation, water treatment:

- Pumping mud out from pond-bottom, taking water into pond, removing waste.

- Sprinkling lime with the dosage from 5 - 10 kg/100m².

- Treating water with Chlorine 10ppm for fresh water farming (in the evening, 10 days before seeding). Treating water with CuSO₄ , 0,3ppm or BKC 1.0 ppm (5 days before seeding) for sea water farming (it’s possible for not treating before seeding, but treat after 2 days of seeding depending on the health status of Pangasius of each pond)

- It is necessary to check all environmental factors such as pH, NH₃, H₂S , suitable salinity.

 

III/ Seeding

1.     Seed choosing

- It shall be screened and tested for banned antibiotics ( Malachite Green, chloramphenicol, nitrofural Leucomalachite ) and other required criterias before choosing seeds. Only seeds which are free of those are accepted.

- Seeds must have equal sizes, quick baiting reaction, flocking, with light blue back, not heteromorphic and not external parasite infected.

2.     Farming Density

- Fresh water: 35-45 fish/m².

- Sea water: 18-25 fish/m².

3.     Seeding method

- Transfering fish from boat to special basket (including unrefined salt mixing) for them  to swim out natually, taking weak and dead fish out.

- Bathing fish with Antishock or Vitamin C 0,05ppm after seeding.

Notes: Seeding action should be done as fast as possible to avoid scratching fish.

 

IV/ Care and management.

1.     Feeding:

- Fish meal : CP . Pangasius is fed with industrial fish meal supplied by reliable company with certification of no usage of GMO and animal originated ingredients as well as banned chemicals.

- Frequency: twice a day. (AM: 9-10, PM : 4-5). It can be increased to 3 times a day for baby fish due to its eating capacity.

Feeding time can be adjusted due to fish health, water supplying regime and time, weather condition.

- Adjusting fish meal must ensure fish well-growth and low FCR.

2.     Water renewing regime

- Renewing water gradually to help fish familiarize with new environment since 7-10 days after seeding

- Renewing water more often when fish is from the weight of 350g.

- Monitoring fish regularly, feeding is not allowed during the renewing period.

- Using siphon in case of bad environment condition ( 3-5 times/crop).

- Increasing water renewing times and having specific treatment methods (eg: using special oxygenic machine to add more ) in case of low oxygen < 1mg/l.

   

3.     Feeding diet

Size of Pangasius	20-100	100-300	300-400	400-500	500-600	600-700	700-900	>900
%Weight of Pangsius	5-4	3.5-2.5	2.2	2	1.8	1.7	1.5-1.3	1.2

-         Lessen about 20% - 40% of the usual amount of feed when using antibiotics

-         When fish’s weight is from 500g, reducing fish feed based on the growth in that period according to standard FCR in each period; not based on % weight of Pangasius.

4.     Mixed Veterinary Medicines

- It is recommended to mix medicines with fish meal to strengthen fish’s health and prevent it from infection on the following instructions:

 

Components	Dosage ( g/kg of dry feed)	Feeding frequency/Month	Notes
Vitamin C	3 - 5	6 - 8	Due to fish’s health status and weather condition
Vimax	1l/40-60 tons of fish		Feeding  3 times (2 days/time) (at the beginning of the second, the third and the fourth month)
Bio Sorbitol	5	4	+ After using antibiotics + Monthly
Bio-Zyme	3	6 - 8	After using antibiotics, due to fish’s health status and weather condition.
Premix	10	4	Due to fish’health status and weather condition

 

·        Bio Sorbitol: In the last two months, feeding frequency depends on the white rate of Pangasius meat. The frequency shall be increased together with water renewing in case of yellow meat.

5.     Fish checking:

- Checking the weight of pangsius every 10 days, 30 fish at least in each, except oversize or undersize fish.

- Regularly checking for external and Endoparasite

6.  Prophylactic System:

- Daily screening fish’s health status.

- Regularly checking pond bottoms to ensure good environment for fish well-growth.

- On detection of fish’s diseases, it must be immediately reported to Aquaculture Department  about specific loss of each pond and sampling for testing.

- Regularly cleaning around fish ponds, taking weak and dead fish out of  ponds, then burying and covering lime for treatment..Also, fishing tools are cleaned with formol 200ppm.

- Treating supply water with CaO in case of infectious outer water source.

- Focus on preventing fish from diseases in ebb season (strengthen renewing water) and  in rainy season (outer water shall be check carefully before pumped in ).

- Using zeolite for pond bottom treatment every 15 days, especially for old and those have no condition to inprove thoroughly.

- Sterilising farming pond water to prevent diseases from recurring after completing a treatment.

- Disease situation around fish ponds shall be monitored very closely before renewing water.

- Carefully monitoring pangasius fish with unusual signs (swimming apart from flock, refusing to eat, swimming unusually).

- In the low temperature months, water in farming ponds shall be maintained at high level. Renewing time shall be calculated exactly to prevent water level from being low over 2 hours.

- In the rainy season, regularly covering with lime after raining .

- If fish has signs of external parasite infection, it should be prevented by using potassium permanganate 2 – 4 ppm (for fish under 1 month) and formol 25 ppm (for fish over 1 month).

- Durring farming, it is necessary to sterilize fish pond 2 - 4 times/month with one of the following chemicals: lime ( 2 - 4kg/100m³: depositing before put into fish ponds.), salt (20-30ppm), BKC (0.7 – 1 ppm), CuSO₄ (0.2 ppm), formol (20 – 25 ppm), chlorine (0,5-1ppm: using in the early morning for monitoring fish).

 

V/ TREATMENT METHODS FOR FISH

1.     Treatment of White mottling disease on fish’s liver and kidney:

- Commonly appeared in fish less than 300g in weight, especially in young fish ready for breeding.

- Components: Florphenicol

+ Dosage:    Raw materials: 20-30 g/ton of fish

                   Finished products: 1.5 - 2 times of dosage as instructed in package.

+ Time required: 5 - 7 days.

- Combining with one of the following sterilization chemicals:

BKC ( 0.7 – 1 ppm ) : using in the morning.

Formol ( 20 - 25ppm): using in the morning, together with adding salt 20ppm in the afternoon.

Fresh water ( 1kg/2000m³ ) : using at 9 am.

2.     Treatment of Head swell, hemorrhage , red spot disease:

- Components:

Sultrim 48% ( liquid medicine)

+ Dosage: 2 - 4 ml/kg of feed.

+ Time required: 5 - 7 days.

- In case of big loss of fish due to serious diseases, Florphenicol may be used.

- Combining with one of the following disinfectant chemicals:

BKC ( 0.7 – 1 ppm ) : using in the morning.

Formol ( 20 – 25 ppm): using in the morning, together with adding salt about 20ppm in the afternoon.

 

Notes on using antibiotics:

- Mixing Vitamin C with antibiotics during treatment is not allowed. Instead, it should be separated into different portions.

- Before treatment, antibiotic outline should be completed and fish prescription is based on it.

- Farming technicians should carefully calculate the amount of medicine used, closely monitor mixing and feeding action to make sure every Pangasius fish in ponds eats all  adequately.

- If fish shows in inadequate clinical response after 3-4 days of treatment, it is necessary to check the treatment methods and report to the supervisor promptly for instruction.

- Farming pond environment should be treated together with water renewing to kill off all germs.

- The maximum time required for a treatment period is 9 days. If  it doesn’t work at all after these days, it is necessary to ask for consultation and sampling for testing again.

- For long duration of using antibiotics with high dosage, sorbitol supplement is added to help fish detoxify its liver.

- Due to short semi-elimination of Florphenicol, it should be mixed with feed twice a day.

- Antibiotics should be combined with enzyme, Vitamin C , sorbitol supplements to help fish with absorption of medicines.

- Based on prehistoric clinical record and treatment medicines for young Pangasius, 2 different kinds of antibiotic may be combined in treatment to reduce the big loss of fish.

3.     Internal parasites:

 - Components:

Vimax:

+ Dosage: 1litter/40-60 tons of fish.

+ Time required: 2 days.

Parasitol ( normal kind )

+ Dosage: 1litter/10 tons of fish.

+Time required: 3 days.

- During treatment time, the following chemicals may be combined for liquidating external parasites:

Formol 25ppm : twice at 1 day interval  ( for pond water treatment).

     Fresh water: 1kg/2000m³ of water : treatment at 9am.

4.     Treatment of external parasites:

Formol 25ppm : twice at 1 day interval ( potassium permanganate 2-4ppm + salt are recommended for fish under 1 month . )

Fresh water: 1kg/2000m³ of water: treatment at 9 am.

5.     Treatment of White gill, white liver diseases:

- With white gill, white liver diseases, feeding shall be cut off for 2 - 3 days, also water is renewed thoroughly and disinfected with potassium permanganate or BKC due to fish’s health.

- Oxygen should be added and stand stably at a level > 4 ppm, also nutriments such as synthetic vitamins, sortbital, enzymes, sufficient feed after recovery.

 

VI. Harvest.

- Vitamin C shall be used in 3 - 4 consecutive days before harvest date, water shall be renewed continuously.

- Antibiotics use shall be stopped since 6 weeks before harvest date.

- An amount of fish feed shall be lessened since 3 days before harvest date, and 4 portions of feed shall be cut off before harvest date.

- Pangasius harvest activity shall not be done in big amount at one time.

- Harvest time shall be finished quickly to avoid negative effects on fish’health as well as fish’s capacity.