Oscar lethargic, not eating, slightly bloated. Need help diagnosing and treating

Maxdevine00

Feeder Fish
MFK Member
Jul 29, 2020
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I don't want to assume anything here but

It could be a chronic condition developing over time (slow nitrate poisoning). If he's been in a 75 alone for 6 years with only small water changes is not nearly enough and will def cause issues. Oscars make massive waste both the kind you see and don't see.

You mentioned at 6 years your O is just under 10 inches....that's small for an adult O. It could be an indicator of not enough clean water over time. Can you post up a pic?
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FINWIN

Alligator Gar
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Dec 21, 2018
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Did he hurt his mouth? It seems oddly shaped. Keep up with the clean water and see if he improves in a couple of weeks. Take another pic then to compare. I see some pitting/hith...that's likely from chronic water conditions. Someone else can chime in on that. If I didn't know better it looks like cartilage is breaking down around his mouth which could also be hith.

Get some Vitamin C powder and add it to the water as you treat. A tablespoon each water change. From here on out change out water to fin level each time. Some of the damage might not change but should improve. Fish with nitrate poisoning often show the symptoms your oscar has.
 
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Maxdevine00

Feeder Fish
MFK Member
Jul 29, 2020
24
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Did he hurt his mouth? It seems oddly shaped. Keep up with the clean water and see if he improves in a couple of weeks. Take another pic then to compare. I see some pitting/hith...that's likely from chronic water conditions. Someone else can chime in on that. If I didn't know better it looks like cartilage is breaking down around his mouth which could also be hith.

Get some Vitamin C powder and add it to the water as you treat. A tablespoon each water change. From here on out change out water to fin level each time. Some of the damage might not change but should improve. Fish with nitrate poisoning often show the symptoms your oscar has.
The mouth shape has been like that since he was 2 inches so I believe genetic. I checked nitrate again yesterday and it’s 5ppm now. What do you think of the eye? Thanks for the help!
 

FINWIN

Alligator Gar
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Dec 21, 2018
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The mouth shape has been like that since he was 2 inches so I believe genetic. I checked nitrate again yesterday and it’s 5ppm now. What do you think of the eye? Thanks for the help!
The eye might clear up with the new w/c schedule. An injury/scrape might take time to heal or be permanent. If his eyesight is ok the odds are better it won't be a cataract. Stay with the clean water!
 

Maxdevine00

Feeder Fish
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Jul 29, 2020
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If I do decide to do antibiotics is there a particular one that would work best in this case? Also, will antibiotics destroy my beneficial aerobic bacteria in the filter? I don’t want to cause any more problems than necessary.
 

jjohnwm

Sausage Finger Spam Slayer
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Mar 29, 2019
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Now, I admit that this comment is based partially upon the fact that, as a Canuckistani, I have grown accustomed to a virtually zero availability of fish medications...but even back before the gummint realized what a danger I was and curtailed my ability to buy such things, I rarely if ever used medication. The invariable and immediate knee-jerk reaction to dose with this or that or the other thing makes me a bit nervous. "We don't really know what's wrong, so...try this...and then this...and maybe a bit of this..."

You have a 6-year-old Oscar who looks like a 16-year-old Oscar but is the size of a yearling Oscar. Such a stunted fish got that way through chronic exposure to at least one ongoing problem; lack of food (not likely because owners just love to watch their fishies eat), poor water quality (nitrate or likely nitrate plus other unknowns), poor genetics (but I think this fish's miniscule size was not caused strictly by genetics), or a combination of the above and possibly other factors.

I won't suggest what medications, if any, would help; literally haven't a clue. But I would bet serious folding money that a 50% water change daily for a week...which would get you down to near-zero, near-brand-new water...followed by an ongoing routine of at least 100% weekly would work wonders. The change won't occur overnight, although improvement should be noticeable pretty quickly, but you won't be maintaining a healthy fish...rather, you will be trying to provide an already weakened fish with better conditions that allow it to heal naturally.

Certainly, use medications if there is a reasonable diagnosis. But change that water! Whatever kind of filtration you have, remember that almost all filters are designed to cycle ammonia to nitrite to nitrate. Most stop there, and that nitrate accumulates; that's not good. And that's about the only thing you can test for and measure; there are countless other compounds and substances that fish is pumping into the water as it eats and respires and poops. We are led to believe that we can ignore them, but that literally makes no sense.

When you change 25% of you water, it makes you feel good to know you are doing good for your fish. But that means that you are leaving 75% of pollutants and toxins in the tank. The next week, you change another 25%...leaving 75% behind. Would you install a toilet in your house that, when flushed, only drained away a quarter if its contents? The accumulation of "stuff" is insidious, ongoing...and can only be addressed in one way.

Change. More. Water.
 

Maxdevine00

Feeder Fish
MFK Member
Jul 29, 2020
24
7
8
27
Now, I admit that this comment is based partially upon the fact that, as a Canuckistani, I have grown accustomed to a virtually zero availability of fish medications...but even back before the gummint realized what a danger I was and curtailed my ability to buy such things, I rarely if ever used medication. The invariable and immediate knee-jerk reaction to dose with this or that or the other thing makes me a bit nervous. "We don't really know what's wrong, so...try this...and then this...and maybe a bit of this..."

You have a 6-year-old Oscar who looks like a 16-year-old Oscar but is the size of a yearling Oscar. Such a stunted fish got that way through chronic exposure to at least one ongoing problem; lack of food (not likely because owners just love to watch their fishies eat), poor water quality (nitrate or likely nitrate plus other unknowns), poor genetics (but I think this fish's miniscule size was not caused strictly by genetics), or a combination of the above and possibly other factors.

I won't suggest what medications, if any, would help; literally haven't a clue. But I would bet serious folding money that a 50% water change daily for a week...which would get you down to near-zero, near-brand-new water...followed by an ongoing routine of at least 100% weekly would work wonders. The change won't occur overnight, although improvement should be noticeable pretty quickly, but you won't be maintaining a healthy fish...rather, you will be trying to provide an already weakened fish with better conditions that allow it to heal naturally.

Certainly, use medications if there is a reasonable diagnosis. But change that water! Whatever kind of filtration you have, remember that almost all filters are designed to cycle ammonia to nitrite to nitrate. Most stop there, and that nitrate accumulates; that's not good. And that's about the only thing you can test for and measure; there are countless other compounds and substances that fish is pumping into the water as it eats and respires and poops. We are led to believe that we can ignore them, but that literally makes no sense.

When you change 25% of you water, it makes you feel good to know you are doing good for your fish. But that means that you are leaving 75% of pollutants and toxins in the tank. The next week, you change another 25%...leaving 75% behind. Would you install a toilet in your house that, when flushed, only drained away a quarter if its contents? The accumulation of "stuff" is insidious, ongoing...and can only be addressed in one way.

Change. More. Water.
Thanks for the detailed response! I will definitely start performing more / larger water changes. Having plants in tank likely gave false sense of security for nitrate lowering. I mainly want to ensure I’m not missing some issue/ disease that a more experienced hobbyist would have insight on. Need to get him through this issue so I can provide better care in the future. Just did another 50% change. I do have metronidazole that came in today and might consider dosing tomorrow if no improvement. Appreciate everyone’s advice thus far!
 

FINWIN

Alligator Gar
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Dec 21, 2018
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Remember, that pitting is not going to suddenly go away. It may fill in over time. Also, check and make sure your filtration is clear of gunk/rotted plant material. That has to be part of the routine as well.

if he starts moving more and eating you're on the right track. Medications will kill appetite so if he seems to be improving stop for a day or two to see if he'll eat.
 
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