A WAY TO RAISE RANCHU ● WATER TEMPERATURE

Ranchu Body Temperature

Ranchu are ectothermic animals, which means their body temperature matches the temperature of the environment. They are also eurythermal, meaning that they are able to tolerate a wide range of temperatures. Depending on the environmental conditions, ranchu will adjust their metabolism.

Optimal temperature for ranchu active growth is between 64-86 F (18-30°C). As the water temperature rises above 86 F (30 C), ranchu activity becomes suppressed, negatively impacting their development. When the temperature drops below 64 F (18 C), ranch's metabolism begin to slow down. Below 43 F (6 C), ranchu enter a hibernation state. Cold temperatures, however, are part of ranchu's natural life cycle and are beneficial. As a temperate climate fish, ranchu enjoy all four seasons.

Temperature Fluctuations

Ranchu is adaptable to a wide temperature range, but only if the temperature changes gradually. It is best if the temperature increases no more then 1.8 F (1°C) degrees per day. A sudden increase of 9 F (5°C) degrees can be lethal, especially for fry and young fish. In an emergency, if the water temperature must be increased quickly, for disease treatment, it has to be done in increments of no more than 4-5 F (2-3°C) degrees per day until the desired temperature is reached. Decreasing the temperature is much better tolerated by the fish, but a gradual change is best.

It is important that the water temperature difference between early morning and noon fluctuates no more than 18 F (10 C) degrees. If it exceeds that - shading, ventilation or a bigger container is required.

Ranchu Activity & Water Temperature 

The range of water temperatures suitable for ranchu is between 30 and 100 F (-1 to +38°C). However, each temperature level dramatically effects the fish's physiology:

• 32-43 F (0-6°C) - full hibernation state, ranchu are inactive
• 44-54 F (7-12°C) - semi-hibernation, physiological functions are slow
• 55-64 F (13-18°C) - intermediate state between hibernation and active state; physiological functions are not up to their fullest 
• 65-75 F (19-24°C) - fish is ready to spawn, gonads develop; pathogens become more active 
• 76-86 F (25-30°C) - active fish growth 
• 87-97 F (31-36°C) - fish growth supressed 
• 98-100 F (37-38°C) - upper water temperature limit for ranchu 
• above 100 F (38°C) - temperature is NOT suitable for ranchu 

Use of Heater 

Although, a heater isn't necessary for day-to-day ranchu keeping, it might be useful in some situations. For the most part, breeders use it to adjust spawning time, to incubate ranchu eggs and to control the beginning stages of ranchu fry. A heater can also be used to aid in treating some diseases.

Advantages:

• setting water temperature as desired 
• controlling to big of a temperature fluctuation during the day 
• to interrupt hibernation 
• adjusting spawning season 
• adjusting hatching date and promote fry growth 
• increase disease treatment outcome 

Drawbacks:

• difficult to keep the same water temperature during water changes 
• lack of four season temperatures may lead to obesity 
• temperatures that are kept the same, lead to more rapid water quality deterioration 
• electrical bill

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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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