It can cause colic in horses but not in sheep or cattle and I guess not in fish lol. We use salty hot water to clean the baths with for the horses but only kills it for a wee while as it is usually in the water as well.
My RES had a aquaone on his tank and it did the job, I used to take the filter out every two days and run it under the tap for a clean especially during a shed. He loved playing under the water flow for ages.