Meds killed my beneficial bacteria??

[barninett]

Please help!
I have had 3 corydoras Melini for a month in a 20g tall. I got 5, but 2 died in the first week (They are still all about 1-1.25in). Yes, the tank was cycled, but new.

This made me paranoid. I have waited a month to get more fish. The issue I was trying to address was very low kH. I have added crushed coral, and things stabilized.

I got 6 young rasbora hets and a VERY small bristle nose pleco yesterday (1.25in). I was trying to be good and add the aquarium coop med trio to the tank since I never did it initially. (paraclense, maracyn, and ich x).

I measured the ammonia and nitrite twice today, and they were BOTH at 0.25. I added 2mL of Fritz complete at 5 hour intervals to address this. Nothing budged.

My corydoras started acting lethargic, and one developed a white spot by its mouth (he has always been the most active one). The new fish all look super active.

I panicked. Did a 40% water change and put the carbon back in my filter (Fluval aqua clear 30).

I don’t have a quarantine tank. I am trying to cycle one, but if the meds kill bacteria anyway, is it worth it?

Should I try dosing the meds again? Maybe just maracyn? I have no experience, but from looking at descriptions, the spot may be colmnaris? How do I keep ammonia and nitrite in check after I add meds?

Thanks in advance for your help!

[tlindsey]

Originally Posted by barninett

Please help!
I have had 3 corydoras Melini for a month in a 20g tall. I got 5, but 2 died in the first week (They are still all about 1-1.25in). Yes, the tank was cycled, but new.


This made me paranoid. I have waited a month to get more fish. The issue I was trying to address was very low kH. I have added crushed coral, and things stabilized.

I got 6 young rasbora hets and a VERY small bristle nose pleco yesterday (1.25in). I was trying to be good and add the aquarium coop med trio to the tank since I never did it initially. (paraclense, maracyn, and ich x).

I measured the ammonia and nitrite twice today, and they were BOTH at 0.25. I added 2mL of Fritz complete at 5 hour intervals to address this. Nothing budged.

My corydoras started acting lethargic, and one developed a white spot by its mouth (he has always been the most active one). The new fish all look super active.

I panicked. Did a 40% water change and put the carbon back in my filter (Fluval aqua clear 30).

I don’t have a quarantine tank. I am trying to cycle one, but if the meds kill bacteria anyway, is it worth it?

Should I try dosing the meds again? Maybe just maracyn? I have no experience, but from looking at descriptions, the spot may be colmnaris? How do I keep ammonia and nitrite in check after I add meds?

Thanks in advance for your help!

Sorry to hear that about your Corydora. Stop adding meds and do 25% daily water changes and don't forget the dechlorinator. Depending on how much beneficial bacteria was lost you wiil either have a mini cycle or start over. If any bacteria survives that will be great because it shouldn't take long for re population of the bacteria. I suggest quarantine and medicate fish in a separate
aquarium or tote always.

[barninett]

Thanks for your response. I am currently trying to cycle a 10g tank for quarantine; however, won’t the same thing happen in there?

I am new to fish keeping, so I don’t have extra seeded filters sitting around to make a quick quarantine tank.

Would you recommend dosing again when things level off again?

[fearlessfisch]

My quarantine tank is never cycled. I put clean, new water and a clean filter in it each time there is a new hospital patient. It is just a small tank to isolate sick fish and medicate them without worrying about disrupting a cycle. It is small so that I can change water quickly and easily, since water changes will have to be frequent when dosing medication in an uncycled tank.

I change water every single day during a quarantine. Be careful to use dechlorinator and match the water temperature so as not to stress your sick fish. I tend to do very large water changes (up to 90 percent, which also gets rid of any nasty bacteria or parasites in the water) and medicate anew with every water change. Some people change smaller amounts of water based on ammonia and nitrite levels, but I think fish benefit from as much clean, medicated water as possible while they are sick; plus, you don't have to worry as much about adjusting medication levels based on old medication that gets left behind in the tank.

In summary, move the sick fish to a small quarantine tank and medicate there, changing water frequently and then remedicating as necessary. Meanwhile, stop all medication in the big tank and work on letting your cycle there regenerate, so that the main tank will be cycled and ready for your fish when they are recovered.



.

[barninett]

Originally Posted by fearlessfisch

My quarantine tank is never cycled. I put clean, new water and a clean filter in it each time there is a new hospital patient. It is just a small tank to isolate sick fish and medicate them without worrying about disrupting a cycle. It is small so that I can change water quickly and easily, since water changes will have to be frequent when dosing medication in an uncycled tank.

I change water every single day during a quarantine. Be careful to use dechlorinator and match the water temperature so as not to stress your sick fish. I tend to do very large water changes (up to 90 percent, which also gets rid of any nasty bacteria or parasites in the water) and medicate anew with every water change. Some people change smaller amounts of water based on ammonia and nitrite levels, but I think fish benefit from as much clean, medicated water as possible while they are sick; plus, you don't have to worry as much about adjusting medication levels based on old medication that gets left behind in the tank.

In summary, move the sick fish to a small quarantine tank and medicate there, changing water frequently and then remedicating as necessary. Meanwhile, stop all medication in the big tank and work on letting your cycle there regenerate, so that the main tank will be cycled and ready for your fish when they are recovered.



.

Thank you so much for your clear answer. I was leaning that way, but I am very afraid of killing my fish that I immediately fell in love with.
You have been extremely helpful.