Oscar fish - just died, tank-mates OK?

[Yamcannon]

Hi everyone! I'm relatively new to the hobby of fish keeping in general, but I think I can safely say I'm addicted.

Unfortunately, my first post here is not a great one. I've encountered my first real fish keeping problem.

I have two Oscar tanks, one is 75 gallons housing two ~5-6 inch Oscars and the other is a 20 gallon.

The 20 gallon grow-out tank houses six juvenile Oscars. One of these Oscars had been not eating, his body got very slender, he was lethargic, hiding, his head looked larger and poop was long stringy white stool. From what I read on the forum pins here it is probably some sort of parasite. I did a water change and a thorough cleaning of the tank, and checked the water parameters which were good. I then ran out to the lfs this morning and picked up API General Cure and dosed the tank accordingly. 3 hours later the juvenile was dead. Just before he died his body began turning white and instead of tucking his fins in like he had been, he flared them out (just trying to give as many details as possible). I've had the juveniles for roughly 2 weeks. I'm quite sad about this as it marks my first fish keeping death, I feel like I should have acted sooner when I noticed he wasn't eating a week ago.

The second issue I have is I briefly had these 6 juveniles in my 75 gallon tank before I realized:
1. My two larger Oscars scared them grey
2. They were afraid to eat
(Which is why I started a 20 gallon grow-out tank)

So now I have the worry that this parasite will potentially affect my two larger Oscars and not just the juveniles in the 20 gallon that I just began dosing today with medicine. Do I also dose the 75 gallon tank?

All other fish seem to be doing well, however, they are eating, active and swimming around. I am now planning on continuing to dose the 20 gallon tank and water change according to the API General Cure directions. Any feedback, advice or future tips and help would be appreciated! Thanks.

 

[Lillypad101]

just a couple questions about the 20 gallon:
How often do you do water changes?
What is the setup like?
Is it filtered, heated, and cycled?
How big are the juvenile oscars?
What are the exact water parameters?
Did you see any of them picking on each other?
Most parasites are contagious, to my knowledge. I had an Ich outbreak in a tank that had an infected fish in it for an hour. It is possible that if the illness was a parasite l, it could spread to your other oscar tank. However, it is not generally recommended to does medications without knowing the exact cause of death.

 

[Yamcannon]

just a couple questions about the 20 gallon:
How often do you do water changes?
What is the setup like?
Is it filtered, heated, and cycled?
How big are the juvenile oscars?
What are the exact water parameters?
Did you see any of them picking on each other?
Most parasites are contagious, to my knowledge. I had an Ich outbreak in a tank that had an infected fish in it for an hour. It is possible that if the illness was a parasite l, it could spread to your other oscar tank. However, it is not generally recommended to does medications without knowing the exact cause of death.

I've done 3 water changes over the last two weeks with the most recent being last night, 50% change. It's filtered, heated to 81 degrees and cycled. 3 juveniles are 1.5 inches in length and the other 3 are 2.5-3 inches in length(trying to get them to 4-4.5 before putting them in the 75 gallon). The Oscar who died was one of the smaller ones at 1.5 inches. I'll have to get the exact parameters for you, but everything looked normal. None of them pick on each other, they all get along quite well surprisingly.

 

[FranciscoB]

Sorry for your loss. I can’t offer insight on the reason for the death.
However, I encourage you to seriously consider the mid to long term of your fish. Oscars in good conditions grow very fast, and get quite big. Not only they need space, but they like to modify their space, and are somewhat territorial. Your big tank (75g) is not large enough to hold adequately even a single Oscar, let alone more. And if things were ideal for the fish, you could be in that situation in just a few months. Not good for them and not good for you. You should rethink the whole plan. Good luck!