Will Aquarium salt affect my fish?

Question

I need aquarium salt for my bettas, but will it affect my 2 Khuli Loaches, my Upside down catfish, and my 2 ghost shrimp?

i have 3 bettas and i want to prevent fungus, they are in a 20 gallon long tank.

Answer 1

Salt isn't a great idea with the Kuhlis and Cat...  These are two scaleless fish and are very intolerant of salt, as they are less capable of controlling their osmotic pressure in its presence.  A much better way to prevent fungus is with proper maintenance, warm water, and a good diet.  Fungus rarely infects fish that are in clean water and have no open wounds, so unless your Betta was injured (in which case, warm, clean water would still be best), there really is little concern of fungus.

EDIT: To treat the fungus with salt, you'd need to go far past levels the Kuhli Loachs and Upside Down Cat would tolerate.  Instead, I would recommend something like Quick Cure or Rid Ich, though copper based medications like Organicure, Aquarisol, or Coppersafe would work too.  Be sure to remove the activated carbon from the filter during treatment and use a HALF dose (for the scaleless fish).

Answer 2

to not affect your other fish i would put the bettas in another tank with aquarium salt until they get better then move them with your other fish once they look better.

Answer 3

I would recommend moving your beta to a small tank for treatment, rather than treat your whole tank and all the fish.  If it's only a hospital tank and they'll only be there a few days, it can be as small as a few gallons if you can dose and maintain it at that size.