Spot on Cardinal Tetra

[Hamsnacks]

A couple of days ago I noticed a single white spot on 1 of the Cardinal Tetras, at first I thought it was simply a grain of sand, but after a day it was still on. My own research online has got me thinking its fungus, and then a closer look today, it seems like the one smaller fin has been nipped at.
The issue is the Cardinal hang around the Serpae Tetra and they like to chase sometimes, the Serpae Tetras are being sold today though.

So what is the best step to do now? There are a total of 25 Cardinal and a bunch of other Tetras, and a few other fish. At the moment every other fish looks good, the Cardinals look a lot better than when I initially got them off the original owner, colors are brighter, definitely have grown as well.

Tomorrow will be doing a 50 percent water change, should I use a chemical, should I let it play out, it's so hard to get the Cardinals due to the driftwood and plants.
I've attached some photos.

Thanks

 

[Colin_T]

Is it an unusual shaped lump that sticks out from the body?
If yes it might be lymphocystis, which is a stress virus that clears up by itself when the stress is gone. However, I need photos of the fish from different angles to confirm that. But you should be able to tell if it's sticking out and whether or not it's lumpy.

If it is white and fluffy it is fungus and Triple Sulpha/ Tri Sulfa (sulpha based medication) should work. Alternatively Methylene Blue will work well on fungus but it will also wipe out filter bacteria so it's best to use Methylene Blue in a separate tank. The sulpha based medications will not affect filter bacteria.

 

[Hamsnacks]

Thanks for the response Colin_T. It definitely sounds like what you're describing in the first paragraph, lymphocytes.

I'll keep a close eye and see if it improves, maybe the stress from getting nipped at.

 

[Hamsnacks]

If it is white and fluffy it is fungus and Triple Sulpha/ Tri Sulfa (sulpha based medication) should work. Alternatively Methylene Blue will work well on fungus but it will also wipe out filter bacteria so it's best to use Methylene Blue in a separate tank. The sulpha based medications will not affect filter bacteria.

I am now thinking it may be Fungus, no improvement, maybe actually got a little bit bigger (still small overall). No other fish has gotten it. But I want it done with, I have tried everything to try to get it out to treat it separately but impossible with the glued on driftwood. So if I go ahead with the API Fungus Cure treatment and dose the whole tank (following the directions of course), after the wait time, I plan on doing a 50 percent water change, should I also wash out the filters media?

Thanks

 

[Matias]

https://www.askjpc.org/wsco/wsc_showcase2.php?id=Y0VrSXBQZUNkbzcxaGZtbEhON20zUT09 Hard to tell from picture but could it be this? I have the same issue now