Sick zebra danio

[Sierra]

Hi, I am looking for an advice. My glo zebra danio has been sick for the past 2 months. He is in a hospital tank separated from the rest. Other fish seems to be ok.
This is an established tank however the fish was new.
First I noticed a red mark on his left side that was an “U” shape. During the past 2 months I have been treating with Salt, melafix, Pimafix, erythromycin, maracyn 2, API general cure, Prazipro.
Nothing worked. Now the red marks are on both sides. He also developed some kind of indentation on both sides. You can see through the fish.
The fish acts normally. Swims happily, always hungry.
Does anyone know what it can be and how to treat it?
The picture is blurry as the hospital tank is a plastic container.
Thank you!

 

[Sierra]

Here my answers
1~What type of fish is afflicted? Glo zebra danio
2~What are your tank parameters ammonia 0, nitrites 0, nitrates 20, temp 78, pH 7.6. During treatment ammonia spiked, did 50% change
3~ How large is the tank? Main tank is 20 gal, w/ same parameters as above, hospital 5 gal
4~What type of filtration are you using? Main tank Aquaclear 10-30 gal, hospital tank sponge filter
5~How many fish are in the tank? Main tank :5 glo zebra danios, 6 glo tetras, all bought around 8/20/22 within a week, added to an established tank over 1.5 year old. All fish is doing good.
Hospital tank: 1 sick danio
6~When is the last time you did a water change and vacuum the gravel? Last water change today , hospital tank 50%, added some gravel from main tank, Main tank water change was on 9/24, about 25%
7~How long have you had the fish? See above #5
8~Have you added anything new to the tank--decor, new dechlorinator, new substrate, etc.? No
9~What kind of food have you been feeding your fish, have you changed their diet recently? Fluval cichlid flakes, Glofish flakes, Omega one blood worms

 

[Colin_T]

Hi and welcome to the forum

Any chance of some decent pictures that clearly show the issue?
The current pictures are very dark.

Don't add chemicals/ medications unless you know what the problem is. It just creates drug resistant diseases that are harder to treat.

 

[Sierra]

Please see more pictures.

 

[Colin_T]

The red sores on the fish look like ulcers. These are normally caused by bacteria.

You have already tried a number of antibiotics (erythromycin, maracyn 2, API general cure) and these haven't helped.

You could take the fish to a fish vet and have them swab the wound, examine and culture it, but that will cost a lot of money and you might not be able to save it.

Personally, I would euthanise the fish and monitor the remaining fish for similar symptoms.

 

[Sierra]

Thank you. I was thinking the same. Sadly it keeps getting worse. Thank you again.

 

[Aiken Drum]

If your fish isnt responding to treatment and there is a risk of contaminating your other fish if you return it to your main tank i would euthanise it rather than have it continuing to have a poor quality of life in quarantine.

Link to a thread discussing euthanising practices.

https://www.aquariumadvice.com/forums/f17/an-overview-of-euthanasia-73775.html

 

[Sierra]

Thank you.
I have a bigger problem with the main tank. Please see my new post under I am devastated thread