Will yellow medication kill all the good baterial in my overhead filter ?

Question

I regret not quarantine my plants and new fishes. I believe the ich (white spot) are floating around my tank. I've added my "Ocean Free" yellow medication to protect the other fishes. I intend to change 20 percent of water tommorrow. I hope the good baterial still remain in the filter to break down the ammonia and the ich will totally be remove ?
How can I ensure this 2 objectives can be achieved without using a heater to increase water temperature? Thank you

Answer 1

What does it say on the package? Typically, it will advise you to remove the carbon from your filter, because the carbon will render the medication usless. I would advise you to ditch the yellow medication altogether. Ich meds are harsh, and there is a much better way to do it.
First of all, get a heater. Unless you have coldwater fish (goldfish) you need heat. It is possible that they developed ich because they were too cold and unable to fight off the parasites. Increasing the water temperature won't kill the ich on its own (unless you raise it above 89F, but don't do that), but it will speed up the process of killing the Ich.

Anyway, I suggest you use SALT to kill the Ich. Start by doing a 50% water change to get rid of the yellow medication and some of the ich parasites. Then add 1 tablespoon of aquarium salt per 5 gallons of water, disolved first in a cup of tank water. You can leave the salt at this concentration for 2 weeks, enough time to thoroughly eradicate the ich if your temperature is above 75F (which it should be if you have tropical fish). Then resume weekly 30% water changes to eventually remove all traces of salt in the water.
This way, your fish will be fine and so will your filter and your beneficial bacteria.

Answer 2

What does it say on the medication ingredients list? Does it contain some sort of antibiotic?If it has some antibiotic, it will most likely kill off some of your bacterial filter.

I believe Seachem makes some Ick medications which are more friendly towards your biological filter.