Do tank antibiotics kill off the tank's bacteria?

[SkarloeysMom]

I was wondering if you treating a tank with Meracyn-2 or Jungle Fungus Clear do you need to re-cycle the tank.
:confused:

[Lady Hobbs]

Anything to treat fungus will set the tank back. However, it also recovers within a few days. Antibiotics and the like do not.

[Sasquatch]

I can't say for Meracyn, but when we used Jungle's Fungus Clear, we didn't need to redo the cycle on our tank.

Another alternative is Tetracycline since it won't kill the bacteria responsible for the nitrogen cycle either.

[SkarloeysMom]

Thanks for the info! That's good to know. I'll make sure and retest everything after I do the next water change.