Confused about Oscar death?

[Zak03]

Hello; I am with Duanes comments all the way. Duanes may not have the exact answer as he is not on the scene as are none of the rest of us but I tend to consider his comments worth considering.



Hello; These are interesting rationalizations but not backed up. A tightrope tank (One on the edge) can go bad in days or even hours. That fish survived two weeks between a WC does not make it follow one week is safe. One way to get clue is the waterparameters with a test kit. 40ppm nitrates is considered high end by many. Shrimp laying around two days is decomposing during that time.
We did not get into the filter and if the media has ever been changed or cleaned.

Good luck

yea, I do trust duanes and his advice has helped me before every time he offered it, but it's just what I'm seeing doesn't match what he is saying. I trust him, I'm just not seeing any correlation and I'm wondering why there's no correlation, or maybe there's another explanation.

And most fish keepers prefer to keep their nitrates under 40 ppm, but that is usually just a personal preference. yes, I agree thats it's safer to keep it below 40ppm, but fish are still okay for the most part at 40ppm. but I understand and agree with you, keeping it below 40ppm is a better option.

 

[duanes]

I never let my tanks go higher than 5ppm nitrate, I consider 40ppm chronically toxic, because where oscars live in nature, nitrate levels would barely go above 2ppm.

 

[Zanzag]

Isnt 40 ppm like panic mode style water change levels?

 

[Serpentine]

I agree that 40 ppm is really high.

First, I am very sorry you lost your Oscar. That's a bummer. They're wonderful fish.

Picking apart some of what you offered for clues.... Why did you cycle the tank with an Oscar in it? Were you aware that the species is sensitive to poor water quality? Some species of fish can handle a cycling tank with minimal discomfort provided they are closely monitored but this may have contributed to your little guy's early demise, stressing and weakening him. Stress does a number on the immune system.

Do you know why your other Oscars died? That's a red flag right there that something is probably wrong in the tank.

Alas, even for juvies that tank is too small and the water changes too infrequent. What kind of filtration is on it? You have some heavy wasters in there, mostly the Oscar and catfish. I would suggest changing water every couple of days if you don't have a much bigger tank. Oscars are dirty birdies. They are both messy eaters and pooping machines. All of the food particles that spew out while they're eating begin to decompose in short order and the catfish can't get them all. 2 days is also too long to leave food in the tank. It would have started to rot by the time your fish ate it, contaminating the water and making your Oscar ill when he consumed it. I try to pull anything not eaten in a few hours. 2-day-old shrimp does no one any good.

African dwarf frogs only get about an inch long so everything in there would eventually eat them. These are the little bitty guys, right? Not African clawed frogs (totally different species and problematic for entirely different reasons). If you can pull the ADFs they can hang out in a small tank. A 5 or 10 gallon will do nicely. They will be safe and comfortable in their own digs. They will actually prefer it. Any tank taller than 15 inches makes it difficult and exhausting for them to come up for air.

API makes a liquid Freshwater Master Test Kit that will last you for years and is very accurate. Even though it's a pain in the butt you should run even the tests you think you don't need, like pH. You might be surprised. What comes out of your tap isn't necessarily what you have after a while with fish swimming in it and possible chemical reactions with driftwood, rocks, substrate, etc..

 

[Ulu]

Did you look in the stomach to see if he swallowed a frog or something obstructive?

 

[RD.]

I totally agree with Duane.

and this

Why did you cycle the tank with an Oscar in it? Were you aware that the species is sensitive to poor water quality? Some species of fish can handle a cycling tank with minimal discomfort provided they are closely monitored but this may have contributed to your little guy's early demise, stressing and weakening him. Stress does a number on the immune system.

The result from ammonia toxicity doesn't always surface immediately. I would strongly suspect that this is where the problem started. I'm not sure why anyone would cycle a tank with any fish in it, let alone an oscar.

 

[duanes]

Maybe a definition of nitrate is called for?
What is nitrate? It is a nutrient.
A nutrient for plants and facultative anaerobic bacteria (fertilizer).
What is fertilizer? manure (poop and pee)
Where does nitrate come from? Metabolism = poop and pee, rotting food etc etc.
If you have an appropriate amount of plants, they will use it.
But an appropriate amount of plants, is probably at least 10 to 50 times the weight of the all fish.
If I don't have that amount of plants, or facultative anaerobes (most aquariums don't)
the only way to get rid of nitrate is with water changes, and the smaller the tank, and larger the fish, the more water changes are needed.
I don't get the aversion to water changes especially when tanks are under 100 gallons.
How hard is it to remove 20 or 50 gallons?
When in the states, I had over 1000 gallons of tanks, and changed 30%-40% every other day.
Would you let your great dane, sit in a room, 24/7 for a week and not clean out the crapp every couple days?
It's no different with fish, just less visible and smelly.
To me 40 ppm nitrate means a significant amount of the tanks water, is fish urine soup.

 

[LBDave]

40gal seems risky. Too much chance of a swing/spike happening quickly. As well as water changes any gravel needs to be cleaned very often. Best with each water change. I have been admonished more than a few times (on forum) for my "overstocked tank". Generally the criticisms are well founded. Oscars need room and big clean tanks and fresh water.

 

[skjl47]

If you have an appropriate amount of plants, they will use it.
But an appropriate amount of plants, is probably at least 10 to 50 times the weight of the all fish.

Hello; Back in my student days I had to do a plant collection in a square meter of ground. That is we placed a square one meter on each side on the ground. We collected all the plants in that square meter. We cleaned the roots some but were careful to not remove roots. We dried the plants out in a low heat chamber over a few days. Then the weight of the plants was taken. It was an eye opener to me in that the mass of the plants was so slight. (note we did not have woody plants in the field) Turned out the plants were largely water when alive.

My point being aquatic plants when dried out have very little mass. I keep live plants in my tanks. I try to be diligent and remove dead or damaged leaves from tanks so they do not decay and release the nitrogen compounds back into the tank. I harvest a portion of the healthy plants every few months with the intent to remove bound nitrates and also to free up space for new growth.

To the OP. Go in peace and run your tanks any way that suits. Good luck.

 

[squint]

I never let my tanks go higher than 5ppm nitrate, I consider 40ppm chronically toxic, because where oscars live in nature, nitrate levels would barely go above 2ppm.

Fish also have thousands of gallons each (or more), no artificial lighting, and aren't kept with species they would never encounter in the wild.

Isnt 40 ppm like panic mode style water change levels?

Nope.

Where does nitrate come from? Metabolism = poop and pee, rotting food etc etc.
To me 40 ppm nitrate means a significant amount of the tanks water, is fish urine soup.

~85% of the nitrogen excreted from fish is vai the gills not urine or feces.

40 ppm nitrate is still below the legal limit for tap water consumed by infants. And there are several paper suggesting that it's unnecessarily stringent.