Oscar attacked by larger Oscar

I recently, 2 weeks ago, was gifted a beautiful Tiger Oscar. I was in search of one to put with my rescued Red Oscar (75 gal, for the time being, anticipating a move to a 125 gal.). I have been selective about taking one in due to size differences. The rescued Red Oscar, is at least 12 in. In length, so obviously I needed a larger Oscar as a tank mate.

I was contacted by someone through a local FB Aquarium forum offering a Tiger Oscar (photo was included, but it difficult to tell size). I was told this fish was 1-2 inches in length. I also currently have a separate 125 gal with other small cichlids in the size group, so I said I'd take him.
Fast forward a few weeks, I meet up with the guy and turns out the T.O. is more like 4.5 inches. Too big to put in with my 125 gal of smaller cichlids. I had him in a fully cycled quarantine tank, and by the next morning the ammonia levels spiked dangerously high, so I had to move him. I put him in the 125 with the smaller cichlids for about a day, and he was tormenting everyone, so I made the decision to just go for it with the Red Oscar. And put them together along with 2 other cichlids the guy gave me. (I really wanted the Oscar most)

Well, he has been doing what appeared to be well in the tank, he had hiding spots, and I never saw the R.O. acting aggressive towards him.

I woke up yesterday, and he looked like the photos posted below. At first I thought one of the larger cichlids in the tank bullied him, but upon looking at him closer, I thought the R.O. tried to eat him. He is missing scales over most of his body, and his tail and fins look tattered.I re-tested the water in the quarantine tank, as it has been set up the whole time, and this time parameters were good. I moved him to it, and began a course of Metroplex (water treatment) and aquarium salt. My questions are:
1. Should I also add vitamin C to help with healing?
2. Is there anything else I should or should not be doing to help him heal?

He is my favorite, I feel so bad for him.

Water parameters:
Nitrate: 20 PPM
Nitrite: 0
Ammonia: .25
Ph: 6.5
Gh: 58
Temp: 78 (well trying to get it to 78, just added a second heater)

 

1. Should I also add vitamin C to help with healing?
2. Is there anything else I should or should not be doing to help him heal?

1. Mix some in with the food. Like a knife's tip, not more. It can easily be overdosed.
2. Big waterchanges and tannins/humic acids instead of salt. Oscars are softwater fish, wound healing is better supported by botanicals than salt.

I see no indication why you should use Metroplex in this case. The fish is injured, not suffering from parasites or an infection. The stuff is just putting extra strain on its system.

 

I'm using Metroplex because everything I read says it heals everything inside and out. A lot of my searches were coming back with a mix of Metroplex and aquarium salt to heal injuries for Cichlids. The larger Oscar had hole in the head previously, I've read if it's hexamita it never really goes away, and with any possible open wounds, I didn't want to run the risk of the little one getting it either. I've only dosed the water once, but can put the carbon filter back in to clear it out.

And change up my recovery care routine. Thank you for you input. I am going to attempt the method you have suggested.

 

I'm using Metroplex because everything I read says it heals everything inside and out.

Unless used for the intended purpose the active ingredients are not helping healing at all. Always look up the properties ofthe ingredients.

A lot of my searches were coming back with a mix of Metroplex and aquarium salt to heal injuries for Cichlids.

There is no evidence that this really helps. In many cases people have to "do something" to feel like they are helping, so often meds are bought and salt added without even thinking about what this actually does. Not saying you're not thinking, but being concerned and reading such unreflected reports may have send you on a path you don't have to go actually.

I've read if it's hexamita it never really goes away

Hexamita, the parasite causing Hole-in-the-head, goes away when treated with the correct med. But depending on the severity of the infestation the intestines might take so heavy damage, the fish may be constitutionally compromised long term.

I've only dosed the water once, but can put the carbon filter back in to clear it out.

Once is fine, maybe do an 80% waterchange additionally to the carbon. You don't use carbon permanently I hope?

And change up my recovery care routine. Thank you for you input. I am going to attempt the method you have suggested.

You don't have to follow my method to the T, as is clear, it's a suggestion. But I appreciate your willingness. I hope your fish makes a good recovery.

 

Once is fine, maybe do an 80% waterchange additionally to the carbon. You don't use carbon permanently I hope?

I said carbon, and meant resin. We stopped using carbon in our tanks a while ago.

Not saying you're not thinking, but being concerned and reading such unreflected reports may have send you on a path you don't have to go actually.

Thank you for your comment. I have made every effort to understand fully the best way to handle this situation. I posted here hoping to get a more educated response than the confusion I was reading. Aquarium salt sounded counterproductive as I know it raises the GH of the tank and Oscar's prefer softer water, but thought other may have known something i didn't about this as therapeutic in times of medicinal use for short term. Same for the Metroplex, I am aware that it is metronidazole and used as an antibiotic, I was thinking in terms of preventative in addition to healing fin and bite mark injuries by using it, since he is stressed, with open wounds, and fish carry tons or bacteria, the idea was to help prevent any secondary issues along with healing.

Everyone on fishlore is great with tactfully sharing information so as not to make someone feel ridiculed or an idiot. (Even if I did make a mistake).

You don't have to follow my method to the T, as is clear, it's a suggestion. But I appreciate your willingness. I hope your fish makes a good recovery.

I understand that, but your suggestion about using the tannins instead of salt and nixing the Metroplex makes sense. I have peat in the house and have set him up with that to help him feel better.

 

I said carbon, and meant resin. We stopped using carbon in our tanks a while ago.

I see. For this special application carbon might be the better choice. Resins usually only remove ions and not bigger molecules.

Aquarium salt sounded counterproductive as I know it raises the GH of the tank and Oscar's prefer softer water,

Actually it doesn't raise GH, it's still just NaCl. But it raises the electric conductivity and salinity, which is not less bad for softwater fish.

Everyone on fishlore is great with tactfully sharing information so as not to make someone feel ridiculed or an idiot. (Even if I did make a mistake).

Admittedly, I myself can be a bit blunt and sardonic if someone ignores every good advice for pages of a thread or reposts the same question until they get the answer they want. (Which still happens once in a while.) But if somebody comes here asking for help and at least trying to learn, I appreciate and honour that very much.

 

I see. For this special application carbon might be the better choice. Resins usually only remove ions and not bigger molecules.

Good to know. I have some left over carbon filter sheets. I could cut a piece and use that. Thank you!

I myself can be a bit blunt and sardonic if someone ignores every good advice for pages of a thread or reposts the same question until they get the answer they want

I find a lot of people tend to do that. It's hard to accept when you haven't taken the best course of action, especially when it comes to a living creature. It's easier to convince yourself everything is okay than going back to step one, or worse admitting you've made a problem worse when you have a sense of responsibility as a caretaker. A lot of people like to pretend they know more than they do, or think they "just know what's best" but it hurts the animals in the long run if someone can't swallow their pride. I used to work at an exotic animal rescue and I would see it first hand with the confiscated and surrendered animals. Ultimately, I just want my little guy (or girl) to get better, and if I have to be told I am doing something wrong so I can learn the correct course of action, I'll take it. Tiger Oscar doesn't have a voice for himself.

 

Good to know. I have some left over carbon filter sheets. I could cut a piece and use that. Thank you!

I find a lot of people tend to do that. It's hard to accept when you haven't taken the best course of action, especially when it comes to a living creature. It's easier to convince yourself everything is okay than going back to step one, or worse admitting you've made a problem worse when you have a sense of responsibility as a caretaker. A lot of people like to pretend they know more than they do, or think they "just know what's best" but it hurts the animals in the long run if someone can't swallow their pride. I used to work at an exotic animal rescue and I would see it first hand with the confiscated and surrendered animals. Ultimately, I just want my little guy (or girl) to get better, and if I have to be told I am doing something wrong so I can learn the correct course of action, I'll take it. Tiger Oscar doesn't have a voice for himself.

Mad respect. I hope your Oscar is doing well.