HIKARI USA INC. Sw Ich X - Ich Treatment With More 16oz

Q: I accidentally bought this for a freshwater tank, will it still work? Is it safe in freshwater?

No it will not. I made the same mistake. You will have to get the freshwater version unfortunately

Q: Does this kill beneficial bacteria if used correctly with water changes as recc.?

not sure what it kills but it does not kill ich!! Got ich in my tank from adding a rock. Called the company they swore it would work, low and behold $2500 in fish and $1000 in coral, it did not work. I admit it was my fault with the rock introduction. Left tank with corals that lived, thru that poison treatment, for 8 months no fish just coral. Ordered more fish and quarantined them for 6 months in copper. no issues. hope that wil help but save your money for more fish, ich sucks