If you need to add it medicinal purposes and just for a short while, for example if your other fish have ich, it will be OK. But over the long run, it's not good to keep any kind of corys in a salted tank. Corys come from naturally salt free water and so their bodies have no means of eliminating it once it is absorbed into them through their skin. As a result, they suffer long term damage to their kidneys and livers which will give them a short life span.
Yes the i have my catfish in a 40 litre tank and i want to put them in my 180 litre tank, i have added salt to my 180 litre tank for medical reasons.
I added salt yesterday and was wondering would it be ok to add them in 4 weeks time, i do a 30% water change each week so would it be safe for them then?.
Thankyou for your help