Recently Deceased Sick Catfish (Ossancora Punctata) Affecting Other Fish?

[Iamfish]

Have you tested your water?

Yes

If yes, what is your ammonia?

0

If yes, what is your nitrite?

0

If yes, what is your nitrate?

80

If I did not test my water...

1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

What percentage of water do you change?

41-50%

How frequently do you change your water?

Every week

If I do not change my water...

1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

Yesterday my Ossancora Punctata was not doing well at all. It had a large lesion above its mouth, one barbel was half gone with white fuzz around it, and a weird red/white patch on both sides of its mid section. It did not make it through the night. I didn't see the fish everyday since it hid a lot but 5 days ago it appeared to be fine. I am now worried about the other inhabitants of my the tank (55 gallons, 1 5 inch Eba, 1 5 inch Hoplo, 1 4 inch Synaptolaemus latofasciatus, and 1 4 inch Silurichthys hasseltii), they all appear to be perfectly healthy, eating and behaving normally. Should I do some sort of treatment on the tank to be safe or should I keep observing for now? I know the nitrates are high, I have no idea why that is they have never been above 15-20 in the time I have this tank running with its current inhabitants. I did Immediately do a 50% wc after testing and will test and do another wc tomorow.

Pics of the Ossancora yesterday before it died

 

[thebiggerthebetter]

Sounds strange indeed but unfortunately our hobby abounds in such cases. Looks superficially like a bacterial infection, akin to fin or skin rot, could be the primary or secondary / tertiary cause of death, who knows.

If worried, you could administer a wide spectrum antibiotic, perhaps one treatment of gram positive and one of gram negative, but this is wishy washy, I believe in such a case there is no telling if this will do more good than harm. In any case, observe the rest closely and diligently and for a long time. Troubleshoot for any potential cause of death. 80 ppm nitrate (could be much higher in reality) still doesn't seem like the smoking gun to me by any means. I doubt it very much, but it wasn't helping, obviously.

Sorry, brother.