NEWS＆TOPICS
- 2016.06.03
- About osmotic pressure
Let me explain why we use salt when the Koi is not in good condition.
To put it plainly, the Koi constantly is making salinity adsjutment so that it exhausts its own energy, physical strength so to speak.
The Koi which has body fluid which contained a few salinity is supposed to made adjustment on osmotic pressure 24 hours a day and that makes it exhaust its energy for the most part.
To compensate for energy loss with making adjustment on osmotic pressure, it makes sence to put the salt in the pond when the koi is not in good condition.
Let me put it this way for making it easier.
As you are aware, it has been said that slug is dying when it is exposed to the salt.
Then, why is that ? This has a lot to do with osmotic pressure.
When the slug is exposed its body to the salt which is under the condition that hyper-osmotic solution than inside covers all over the slug.
Under that circumstances, osmotic pressure makes body fluid of hypo-osmotic pressure inside flow to outside body of hyper-osmotic pressure.
That ends up in the cells inside of slug is deprived of water causing malfunction and slug is killed as a result.
On the other hand, as far as the fresh water fish is concerned, Koi has body fluid which salinity concentration is higher than water in the pond.
Osmotic pressure works in such way that flows from low concentration to high concentration.
That means water seep into the koi. Which makes me wonder, how the koi deal with this huge amount of water for its body.
Fresh water fish does not drink water at all, instead, excretes the water getting into its body as urine.
This function is what its kidney function is specialized in working.
Making adjustment on osmotic pressure should be tough and exhausting, so using salt means that set up the condition temporarily in which koi do without making adjustment on osmotic pressure.
Incidentaly, the fresh water fish in the river is said to move to estuarine region (brackish water) when it gets bad in health condition.
This would explain it takes huge amount of energy to make adjustment on osmotic pressure.
