Sick Cardinal Tetra

[Okesa]

As I was leaving work this evening I noticed that one of the Tetra has several fairly large lumps on its torso. I changed the filter in the tank last Friday and didn't notice anything strange at the time. Water temperature is 25° C. I didn't have any test strips on hand to check the other parameters, but the tank has been fairly stable for months. The fish (6 cardinal tetras, 4 albino corys, a dwarf gourami, and 4 amano shrimp) were added back at the beginning of September, and the tank cycled for over a month with just plants before that. 

I plan to check the water parameters first thing on Monday, but in the meantime, if anyone has suggestions for what course of treatment I should use, and what supplies I should purchase over the weekend, I would really appreciate it. 

Video - slightly more clear than the picture

Edited November 26, 2021 by Okesa

[Flumpweesel]

That's bad link  (took me to pile of tiktok nonsense) 

[Okesa]

@Flumpweeselsorry! I was using the YouTube app and it must not have copied the correct link. Should be fixed now! 

[Colu]

Looks like the start of neon tetra disease or  a bacterial infection  am not sure what medication you have available in Japan I would definitely treat with antibacterial medication and add a small amount of aquarium salt 1 table spoon for 5 gallons at  that level salt shouldn't harm your plants and it improves Gill function and add essential electrolytes to help reduce stress in fish I would also look at your water parameters just in case something off

Edited November 26, 2021 by Colu

[Okesa]

Got to work this morning, and our sick tetra was still alive!

Checked the parameters and nitrate and nitrite were both 0, GH was around 8, KH was around 10, pH was around 6.8 (it is always low - I have added cuttlebone to try to help), and Cl was 0. 

I was able to get some aquarium salt and some antibacterial medication (Sodium nifurstyrenate) over the weekend. I set up a quarantine tank for the fish that is obviously sick and dosed it with both aquarium salt and the antibacterial, and added some salt to the main aquarium. I'll be watching the other fish to see if they look like they are developing any infections and hopefully we will get everyone healthy. 

Thanks for your help!

[xXInkedPhoenixX]

Poor little one, hope you have success and they get better!

[anewbie]

Look like fungus to me though a clearer picture would help. If fungus don't treat it - it will heal on its own as the wound heal. What frequently happens is a fish will scrape itself and a blob of fungus will form over the wound. As the wound heals the fungus goes away - takes about 2 weeks.