A WAY TO RAISE RANCHU ● CULLING ROUND - I

First Culling Round - Two Weeks After Hatching

The fry size should be around 1/2 in (13 mm). The tail by now is clearly open and it is time to make first culling round. The selection is performed looking from above.

Main concern during this time is to look for the straight body line and open degree of tail shoulders, as well as open tail shape, as indicated in the picture below. Every other concern must be left for the next round.

The number of fish during the first round will be greatly reduces. First remove fish with obvious defects, then do more precise selection until the appropriate stocking density is reached. Once the needed stocking density reached you can only take out fish with obvious defects. Usually, the overall fry number should be reduced down to 10-15% after the first culling round is complete.


Negative Points To Look For (blue line shows defect):

1. Wild carp tail regression, very easy to recognize
2. The tail is not fully open; red line indicates desired angle of 160°-170° (ideally 180°), sometimes difficult to recognize, questionable cases can be left for round two 
3. The tail in not open, left and right sides irregular 
4. Twisted body or tail peduncle line (often happens when hatched in low water temperature) 
5. Tail core forms a dark line continuing into the tail peduncle, if clearly visible 
6. Tail split more then 1/2 of the center line length 
7. No tail split. Although, not a fault 
8. Asymmetrical tail shoulders 

Also look for:

• fish that can’t swim straight
• fish with poor growth rate
• fish with any other obvious defects

During the First Round

Leave the fish with symmetrical tail, that is open no less then 160°-170° (ideally 180°, as in picture #2). Examine the tail tension. Keep in mind that tail tension has tendency to soften with time.


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Links to published chapters:

● INTRODUCTION
● WATER
● NOTES ON GREEN WATER & WATER CHANGE
● WATER TEMPERATURE
● AERATION
● SUNLIGHT AND SHADE
● CONTAINERS FOR RAISING RANCHU
● FOOD
● FEEDING REGIMENT
● BREEDING & SPAWNING
● RAISING & GROOMING FRY
● GROOMING KUROKO AND TOSAI
● CULLING
● SELECTION METHODS
● CULLING ROUND - I
● CULLING ROUND - II
● CULLING ROUND - III
● CULLING ROUND - IV
● CULLING ROUND - V
● FORSEEING RANCHU CHANGES IN THE FUTURE

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A WAY TO RAISE RANCHU ● SELECTION METHODS

The ability to recognize strengths and weaknesses in fast growing ranchu fry is very important. However, no matter how good the quality of a ranchu is, there will always be some fault.

It is wrong to look for all imperfections at once, when performing culling. The best is to seek out major drawbacks and leave off minor imperfections and not to overlook the fish's charm and overall appearance.

It takes years of experience and training to start recognizing of what is important and being able to balance between good traits and faults for achieving the iconic ranchu look.

Selecting Between the Good & the Poor Fish

During culling, skilled person will search for a good fish, while novice will often look for a bad fish. Partly, because it is easier to identify the bad fish first, especially when you have a little experience as what to look for. However, there are advantages and disadvantages in both methods.

Looking for a good fish:

• culling must start early 
• by selecting only good fish, the number is drastically reduced 
• promising fish can be overlooked 
• moderate to high experience is necessary 

Looking for a bad fish:

• promising fish can not be overlooked  
• time consuming 
• hard to dramatically reduce the number of fish
• suitable for a novice

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Links to published chapters:

● INTRODUCTION
● WATER
● NOTES ON GREEN WATER & WATER CHANGE
● WATER TEMPERATURE
● AERATION
● SUNLIGHT AND SHADE
● CONTAINERS FOR RAISING RANCHU
● FOOD
● FEEDING REGIMENT
● BREEDING & SPAWNING
● RAISING & GROOMING FRY
● GROOMING KUROKO AND TOSAI
● CULLING
● SELECTION METHODS
● CULLING ROUND - I
● CULLING ROUND - II
● CULLING ROUND - III
● CULLING ROUND - IV
● CULLING ROUND - V
● FORSEEING RANCHU CHANGES IN THE FUTURE

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A WAY TO RAISE RANCHU ● CULLING

The Purpose of Culling

It is absolutely necessary to perform selection and culling to keep up and improve upon ranchu quality. In one spawn, ranchu can produce a lot of fish with undesirable characteristics. Strict selection of the fish with true ranchu qualities will assure that ranchu breed stays alive and continues its high quality traits.

During Ranchu Culling

Choose shady and well ventilated place during culling process. Sudden water temperature change will kill the fry. It is outmost important to keep the temperature as even as possible during selection and transfers of the fry from one container to another.

Choose large enough container size for culling and do not overstock. Overstocking and too small container will result in lack of oxygen. Also, water temperature in small container tends to fluctuate more freely in response to the air temperature.

To prevent water temperature change and lack of oxygen, floating box with netted bottom can be used to house the fry. The box floats in the pond, keeping the water parameters stable.

Culling Mistakes 

Often, a novice tends to keep most of the fish and performs selection and culling much later then required. The culling rounds must be performed on schedule. Overstocking may result in underdeveloped and lower quality fish.

During the early fry stages it is easier to identify many defects and major imperfections. That's why first culling round is performed drastically. The following rounds require more mastery and training, as one searches for the fish with superior qualities.

_________________________________________________________________________________

Links to published chapters:

● INTRODUCTION
● WATER
● NOTES ON GREEN WATER & WATER CHANGE
● WATER TEMPERATURE
● AERATION
● SUNLIGHT AND SHADE
● CONTAINERS FOR RAISING RANCHU
● FOOD
● FEEDING REGIMENT
● BREEDING & SPAWNING
● RAISING & GROOMING FRY
● GROOMING KUROKO AND TOSAI
● CULLING
● SELECTION METHODS
● CULLING ROUND - I
● CULLING ROUND - II
● CULLING ROUND - III
● CULLING ROUND - IV
● CULLING ROUND - V
● FORSEEING RANCHU CHANGES IN THE FUTURE

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