I do not think they "hurt", but it's questionable as to the effects.
I still think folks will do much better doing basic things to care for their fish like good water changes/good foods.
I recall one guy addign caffine to the water to act like the coffee trees near one location in the wilds.........
Yes, there is plenty on line about it, all anecdotal.
Where is a base line to compre them too?
What consititutes improved fish health???
My fish are healthy enough as it is.
But then again I take good care of them.
New fish are well acclimated, all basic stuff.
But this is a plant forum, the question is are they better for plants, I'd have to say based on everything I've read and seen to date, no.
Do they hurt? Probably not.
Do they work? Likely the same answer, but I might be wrong.........but I doubt it.
Regards,
Tom Barr