question about keeping freshwater and brackish fish together

[AQUAMONSTER]

So I'm the fish guy to my future inlaws. I clean their tanks and stuff. In his tank tho he has

gold sev
convict
blood parrot
african knife
blue acara
and a jade goby

how much salt could i put in to confort the jade goby but not kill the cichlids?

 

[AQUAMONSTER]

?

 

[MChorse13]

none you cant just put in a little bit of salt to "confort" the jade goby. you could set up another tank for it tho