A question about Osmotic shock

[seaplane]

How is it that you can put fish into a Freshwater dip and back into saltwater without worry, but it's a problem if you take one from a hyposalinity , say 1.017, into 1.025 ?

 

[hybridazn]

Hyposalinity treatment takes weeks to have the effect needed to eradicate ugh permanently. During these weeks fish become acclimated to the salinity. A fresh water dip is a quick, temporary "relief" for the fish, they aren't in there long enough to get shocked. If you leave a fish in freshwater for longer than 15-20 minutes they will go into shock.

 

[Big G]

How is it that you can put fish into a Freshwater dip and back into saltwater without worry, but it's a problem if you take one from a hyposalinity , say 1.017, into 1.025 ?

The recommended freshwater dip to help with ich, velvet or flukes, worms is 5 minutes max to get the parasites to release. It literally causes the parasites to spasm and depending on the parasite die rather quickly. The fish can handle the 5 minutes unless they are too weakened by the parasite's attacks. And then you do lose a fish.

~ Gary