Oscar fish can't breathe other three are fine

I have a 129 gollon tank. Been set up for about 5 months now. Hob emporer 400 and a marineland c-530 can. Undergravel filter also. 1 common oscar, 2 tiger oscars and 1 albino oscar. Also a pleco. All fish are normal and acting great except 1. The common oscar is hiding, breathing heavy, not eating, has white poop hanging from him, a couple scales look to be falling off. Otherwise his fins and head look perfect. All my water tests are coming out great. Idk what to do? I've read so many things online but don't see it directly applying to his situation. I was feeding a mix of live roses and gold fish but stopped a few days ago after reading that they can get your fish sick! Please help!

 

Hm. White long stringy poop?

 

Yes sir. It finally broke off. But yes before it was. Just started this morning. They were fine yesterday.



See his scales are falling off






He has two spots where he has a scale or two missing. My fish get along. They grew up in a 40 gallon before I got them this tank.

 

Internal parasites likely. Loss of appetite, lethargy and long white stringy poop.

I would suggest going for 1 round of treatment of praziquantel. If that doesn't improve the situation, follow up with a treatment of metronidazole. Oscars are infamous for internal parasites.

Now, regarding the scales, I actually have no idea what it is. It could be related to the parasite or smth else completely

 

Thank you sir. I bought a 20 gallon long aquarium for a hospital tank. When I got home with it 3 of the 4 were breathing heavy. Now I'm treating the whole tank with apI melafix. I showed the old guy at the pet shop the same stuff I showed here and this is what he told me to do. I hope they make it!

 

To be perfectly honest, melafix is pretty. Well. Ineffective. Additionally, it only works against very specific strains of bacteria.

For internal parasites, you'll need the 2 medications I shared.

Lastly, heavy breathing.... Do you have a testing kit to test the water parameters?

 

Yes I have the apI master test kit for freshwater. I never realized how inadequate the test strip are til I bought this kit. Like I said all levels are good. My nitrate may be a little high or right at the 40ppm color. But I have all my carbon filters out of all my filtration systems. I'm going to get the two meds you shared. I've had these fish over a year. I bought them when they were about two inches long. My local aquarium store guy has worked there for years so I kinda trusted him. But the more you help me and the more I Google and read the more I'm leaning to your conclusion. Should I do a water change to get most of the melafix out then use the two you are recommending?

 

PrazI doesn't work well on internal parasites metro does. If it's still eating find some NLS Hex shield and feed it to it.

 

It won't eat anything. It still poops white though.

 

API general cure is a mix of prazI and metro so you could try that. Metro is much more effective when it's eaten than when it's added to your tank water. Epsom salt will help when dosed at 1 tbsp per 5 gallons.

 

Well sadly he died last night. I had went to petco to see if they had apI general cure. Sadly they did not and all other places closed before I could get there. I found it this morning at pet supplies plus. Hopefully I got it in time to save my other three as now my albino has the stringy white poop and breathing heavy. I did a water change and administered the apI general cure. It was pretty expensive. I don't know the best pet suppliers but online is the best I've found. I got more meds coming at half the price. I also got the garlic additive for there food.
I'm hating myself today for ever feeding them goldfish or rosies. I wish I had read more about it before I did that. He was one of my original pair of oscars and I'm pretty bummed I pretty much fed him his death sentence. And now I know to keep various meds on hand and my hospital tank setup.

 

I also have the hex guard food ordered as no local pet stores had that either.

 

Welp. Sorry to hear that. Going forward, my personal suggestion is to never ever feed feeder fishes. Or feeder anything. Pats pats. Lesson learnt I guess?

 

All but one died. I started a new thread on how to clean the tank. Any thoughts. Break it all down and start from scratch or bleach it, salt it, over medicate it? Will my driftwood hold any parasites. All my other decor I can boil. The last oscar and common pleco are in separate quarantine tanks getting meds. Neither show signs of the worms/parasite.