My mother got a fish tank and added in an iridescent shark. It acted fine for a few days but it suddenly started to hide and not move. The only other fish is a blood parrot cichlid with a deformed mouth. I found out just now that she added aquarium salt around the time it started acting differently. So the question is could the salt be the cause of the shark acting differently. Any help will be much appreciated because I have no experience with salt.