A WAY TO RAISE RANCHU ● AERATION

Adequate aeration is important in supplying water with oxygen. It also aids in better water circulation and equalizes temperature between different layers in the pond.

However, vigorous aeration can have a negative impact on developing ranchu, especially their tale formation. It is very important to bring aeration to its minimum or avoid it all together during eggs hatching and fry development and, when the tail starts to form and open.

Advantages of aeration:

• supply of oxygen to the water 
• release of carbon dioxide from the water 
• mixes water for more uniform water temperature 
• delays deterioration of the water quality 

Drawbacks of aeration:

• too much aeration loosens the tail tension and effects its shape 

Oxygenation And Water Surface 

Pond surface is important for oxygenation. If covering or shading the pond, attention should be paid not to obstruct the airflow and gas exchange. It is necessary to provide good ventilation if the pond is inside or when air temperatures are high.

The Amount of Dissolved Oxygen And Water Temperature

There are two factors that effect how much oxygen is dissolved in the water: temperature and pressure.

With shallow pond used for ranchu, water pressure does not have much effect. The amount of dissolved oxygen will primarily depend on increase or decrease in temperature. As a rule, with temperature increase the amount of dissolved oxygen will proportionally decrease:

• 32 F (0°C) - 14.16 ml/L 
• 34 F (1°C) - 13.77 ml/L 
• 41 F (5°C) - 12.37 ml/L 
• 50 F (10°C) - 10.92 ml/L 
• 59 F (15°C) - 9.76 ml/L 
• 64 F (18°C) - 9.18 ml/L 
• 68 F (20°C) - 8.84 ml/L 
• 77 F (25°C) - 8.11 ml/L 
• 86 F (30°C) - 7.53 ml/L 

In the summer, due to higher temperatures water oxygen levels are at their lowest. Ranchu requires more oxygen in the summer, as it is most active. If there is a lack of oxygen in the water, ranchu will be swimming “nose up” at the surface gasping for air. Sufficient aeration is required, as well as the appropriate stocking density.

Oxygenation And Green Water

Phytoplankton in green water photosynthesizes and supplies oxygen to the water. When water gets over saturated with dissolved oxygen, it starts to escape in the form of gas. So called “gas bubble disease” may occur, when oxygen gas bubbles appear in the fish bloodstream and become visible on gills, fins and eyes. It can cause a secondary infection or even be fatal.

When using green water, additional aeration may not be necessary. Still, keep an eye on oxygen level becoming too low.

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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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