Oscar: lump and small open sores. What is this?!

JSlead

Feeder Fish
MFK Member
Oct 17, 2020
23
3
8
49
Have you tested your water?
Yes
If I did not test my water...
...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
If I do not change my water...
...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.
Dear Monster Experts,

I’ve had this (presumed) female Oscar for about 3 years. 125gal tank. I change 50% weekly: 2/3 well water, 1/3 RO. PH is 8, which I know his high, but stable. Water tests are always exceent. Nitrates get up between 20-40 and then cut in half at WC.

Tankmates: 1 Firemouth, 5 small Silver Dollars, Raphael Catfish.

All fish doing well until a week ago. I first noticed two tiny open sores on Oscar’s jaw, like little pin pricks. Then a few days later I saw a lump on her jaw about the size of a pea, near the sores. Today I see more sores, some on the lump itself (see pics).

1683406489621.jpeg

Any ideas what this could be?

Thanks for any help.
 

FJB

Blue Tier VIP
MFK Member
Dec 15, 2017
1,890
3,209
439
Philadelphia, PA
Nothing about rubbing on glass. Instead, it is more likely a combination of insufficient water changes leading to high nitrate (20-40 is quite high if that is the prevailing level), and high pH. Increasing water changes should help, but your water is not the best for either Oscars or silver dollars.
 

JSlead

Feeder Fish
MFK Member
Oct 17, 2020
23
3
8
49
Thanks for the replies. Well, this Oscar passed away last week. This swollen/ open sore area got worse and worse and worse, and she died. I tried to treat with a couple meds over the last few weeks but it made no difference.

To FJB:
Water changes: I change 50-60% of the water weekly. It’s hard to tell where the nitrates are at water change time because the test tube colors are so similar, but it’s somewhere in that 20-40 range at water change time, and obviously gets cut in half by the water change. What should I be shooting for, if that’s not enough? Maybe a midweek WC as well? Or a few weeks of double changes to get it at a more manageable level?

Also, you stated that this is not proper water for these fish. Do you mean nitrate level, PH, or both? Any recommendations?

Lastly, since this is the second Oscar I’ve lost to this incredibly terrible disease this year (different tanks), I sent this one off (via my vet) to a university for analysis. I’m hoping to find out what is killing them.

Thanks, all.
 
  • Sad
Reactions: deeda

FJB

Blue Tier VIP
MFK Member
Dec 15, 2017
1,890
3,209
439
Philadelphia, PA
Hi again. I am very sorry about the loss of your fish.
Regarding your question about levels of nitrate and water change levels to shoot for. It is very hard to say, as background nitrate levels vary widely in tap water at various locations, and a lot depends also on presence/absence of plants, feeding regimes, types of food, etc. However, nitrate levels to shoot for are undetectable (if possible), or as low as possible (10-20 max) by water change day. Water changes and plants (even floating plants meant to be eaten) are good tools to help reduce nitrate levels.
Oscars have evolved in waters with low pH and very low nitrate. Even as adaptable as mass produced oscars may be, combinations of high pH, high nitrate and insufficient water changes are a recipe for problems.
RE- water changes. With the biomass you had in the tank, I would be aiming at no less, and better more than 100% water changes weekly, best given in 2-3 smaller (but cumulatively equal) water changes. So yes, at least a mid-week water change may be a good idea.
I have 2 125gal tanks with less biomass and both are heavily planted. I also only feed 4 days a week. I do no less than 75% water changes weekly, and try to do more if I can.
 

JSlead

Feeder Fish
MFK Member
Oct 17, 2020
23
3
8
49
Hi again. I am very sorry about the loss of your fish.
Regarding your question about levels of nitrate and water change levels to shoot for. It is very hard to say, as background nitrate levels vary widely in tap water at various locations, and a lot depends also on presence/absence of plants, feeding regimes, types of food, etc. However, nitrate levels to shoot for are undetectable (if possible), or as low as possible (10-20 max) by water change day. Water changes and plants (even floating plants meant to be eaten) are good tools to help reduce nitrate levels.
Oscars have evolved in waters with low pH and very low nitrate. Even as adaptable as mass produced oscars may be, combinations of high pH, high nitrate and insufficient water changes are a recipe for problems.
RE- water changes. With the biomass you had in the tank, I would be aiming at no less, and better more than 100% water changes weekly, best given in 2-3 smaller (but cumulatively equal) water changes. So yes, at least a mid-week water change may be a good idea.
I have 2 125gal tanks with less biomass and both are heavily planted. I also only feed 4 days a week. I do no less than 75% water changes weekly, and try to do more if I can.
Thanks for your comprehensive reply. Man, I really thought I was doing an excellent job here. I guess not. I’ll do some testing and figure out a better WC regimen.

Also, I have always fed them daily. I suppose I should back that off too.
 

Fishyboy🐟🐟🐟

Candiru
MFK Member
May 31, 2023
615
197
46
Thanks for the replies. Well, this Oscar passed away last week. This swollen/ open sore area got worse and worse and worse, and she died. I tried to treat with a couple meds over the last few weeks but it made no difference.

To FJB:
Water changes: I change 50-60% of the water weekly. It’s hard to tell where the nitrates are at water change time because the test tube colors are so similar, but it’s somewhere in that 20-40 range at water change time, and obviously gets cut in half by the water change. What should I be shooting for, if that’s not enough? Maybe a midweek WC as well? Or a few weeks of double changes to get it at a more manageable level?

Also, you stated that this is not proper water for these fish. Do you mean nitrate level, PH, or both? Any recommendations?

Lastly, since this is the second Oscar I’ve lost to this incredibly terrible disease this year (different tanks), I sent this one off (via my vet) to a university for analysis. I’m hoping to find out what is killing them.

Thanks, all.
To be honest sounds like hole in the head which is a uncommon disease with Oscar’s which causes open sores and death if untreated, it can be treated if any future Oscar’s have it, rip to your Oscar, Oscar’s have such great personality’s
 

JSlead

Feeder Fish
MFK Member
Oct 17, 2020
23
3
8
49
To be honest sounds like hole in the head which is a uncommon disease with Oscar’s which causes open sores and death if untreated, it can be treated if any future Oscar’s have it, rip to your Oscar, Oscar’s have such great personality’s
Hello,

I’m well familiar with HITH. This wasn’t it. I ended up sending the fish to a university lab for analysis. They said it’s an external flesh-eating bacteria (they had a huge multi-name for it; ulcerative necrotic dermatitis and some more descriptors.) Anyway, now they’re growing a culture of the bacteria so it can be identified to the exact species so hopefully it can be treated; I assume it’s still living in my tanks.

I will report here when I have news.
 
  • Like
Reactions: deeda

Fishyboy🐟🐟🐟

Candiru
MFK Member
May 31, 2023
615
197
46
Hello,

I’m well familiar with HITH. This wasn’t it. I ended up sending the fish to a university lab for analysis. They said it’s an external flesh-eating bacteria (they had a huge multi-name for it; ulcerative necrotic dermatitis and some more descriptors.) Anyway, now they’re growing a culture of the bacteria so it can be identified to the exact species so hopefully it can be treated; I assume it’s still living in my tanks.

I will report here when I have news.
I guess try just treating with with methayine blue and antibiotics
 
zoomed.com
hikariusa.com
aqaimports.com
Store