Aquarium cycle crashed while treating fin rot

[Lexi B]

Temperature: 78

Ph: 7.6

Amm: 0.5

Nitrite:1

Nitrate: 20 (nitrate is also in my tap at about 20ppm, but I have live plants)

My Betta has been through a lot these past couple weeks. His fin rot I believe was originally due to stress, since after an accident that almost killed him he spent a week laying on the floor of a breeder box. When he was able to swim around and energetic, I was able to move him to a new cycled tank, and that's when I started treating him for fin rot. 

I used maracyn as directed, and it cleared on the edges of his tail and the other fins have healed in the past week. But the deepest injury on his tail is progressing, and after testing the water I've found my cycle has crashed. 

My plan was to treat another dose of maracyn and Ich-x, but now that my tank has parameter issues I don't know if it's better to hold off on medication to keep the water pristine with changes or not. 

I'm very concerned for him. Most of his tail is ok except for the deep damage, which is getting too close for comfort. He's still energetic and eats like a pig, though.

[laritheloud]

Any antibiotic in the water column has the potential to crash a cycle, especially one that hasn't been established for a long time. I would do frequent water changes and treat the fish as he needs, and when he seems to be on the mend, keep up the frequent water changes until parameters stabilize.

[xXInkedPhoenixX]

I agree with @laritheloud it's true, meds can crash a cycle. So just do frequent smaller water changes (I wouldn't do more than 20%, personally I've found more than that can do more damage than good.), detoxify with whatever it is you use (I use Prime), monitor your levels and treat the fish with the meds you chose. 

When done with medication be prepared to continue with the water changes and detoxifying. Use bottle beneficial bacteria if you want and/or treat it as a fish in cycle if you don't have already cycled media you can put in once medicating is over. 

Edited December 11, 2021 by xXInkedPhoenixX

[Colu]

You could treat with medicated food that's less likely to affect your benefial bacterial and then you can do small daily water changes and add prime to detoxify any nitrites or ammonia  he's how I dose maracyn in food 1 table spoon of pellets one scoop seachems focus add a few drops of water one cap full of seachems garlic guard and a quarter of a packet of maracyn feed for 7days you can keep the medicated food in the fridge  in between feedings

Edited December 11, 2021 by Colu

[HH Morant]

I think it is a great idea to put the meds in food. 

That way you can do water changes as required to combat ammonia/nitrites. Regardless of how big your routine water changes are, you have to take into account how much ammonia/nitrite is in the tank. Sometimes it is not enough to remove 50% of the ammonia your fish are breathing.

It has been a while since I had an ammonia issue, but I have done 75% water changes in the past to combat ammonia. One 75% water change is equal to two 50% water changes.

There are differing opinions about whether Prime or any other water conditioner detoxifies ammonia or nitrites. I do not believe they do. What Seachem describes as "chemically unexpected" is described as "chemically impossible" by others, including the chemist who writes the articles at aquariumscience.org.

If I had a choice between pouring some Prime in the water and doing a water change, I would definitely do the water change.