PLEASE HELP (Oscar fish weird behavior)

[LBDave]

General Cure is metronidazole with praziquantal. Shouldn't that work also? What dosage Metronidazole do you recommend?

Rather than use Prazi which is not needed I just used metro for HITH.
Seachem - MetroPlex
Link has directions

 

[LBDave]

Use max dose. Just FYI, if it has affected the brain it may be too late. But worth a try.

 

[revanblaze]

Hello everyone, please only respond if you have experience on the matter, thank you for your time

tank set up
size: 180 gallons
fish: 1 Adult Oscar fish, 7 silver dollars, 1 Adult pleco, 1 Adult bichir
water parameters: PH 7.1, Ammonia 0ppm, NO2 0ppm, NO3 0ppm
filtration system: UV filtration, Fluval fx6, 2 airstones, airstone filter
temp: 76 F
live plants and fake plants, as well as rock hides and driftwood

had silver dollars living on the other side of a divider for a while they grew a bit bigger for 4 months. removed it and have been living peacefully for about a 3 weeks. the Oscar is 4 years old and has lived its whole life with the bichir. was recently moved into the 180 gal from a 75 gal 8 months ago. It's lived about 8 months with the pleco and occasionally harasses it, but rarely even sees it

What is the problem:
I love this oscar fish more than anything, I had him transported across the US when I moved after getting things set up (had my parents take care of him while I set everything up). he's been here for now 9 months. hes appeared healthy since a month ago. recently I tried introducing another oscar who was a bit smaller than him and very non aggressive from a 75 to the 180. had them separated by a divider. decided it would be better for them to be separated and put the smaller one back into his 75. during the time they were in the tank together I think their may have been signs of hith forming on my adult oscars head (one fairly big hole on his side, but only a faintly light spot on his forehead). I treated the whole aquarium with general cure. (Water parameters had a slight ammonia spike previous to this about 2 weeks after cleaning my filter to about .25ppm) re-stabilized the aquarium with a 50% water change after treatment. its been about a week now and hes(idk how to post videos here I will try) been spending most of his time on the right side of the tank and he'll bot in circles, or left and right rapidly and aggressively. I am very worried about this behavior as he's never really done it before. today he's just been hanging out on the right side of the tank doing this behavior. I'm also severely worried about the potential hith and am planning to do a second wave of treatment tomorrow. I think the first wave did help as the one hole seems to be healing. I've been extremely nervous and worried for my oscar, I just want him to be happy and healthy life. I'd appreciate some advice, Idk what this behavior is, the tank is well aerated, his gills and fins look healthy, he doesn't eat very much, but is eating his food. Thank you for reading

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So I thought I'd do an update post for any future fish keepers with a possible similar situation and some information I have found. The behavior seen above is almost certainly territorial behavior. I found that removing all fish except the one he's very familiar with caused a decrease in this behavior. he still sometimes does it when I'm moving things, trying to take photos(for this post) or now if the pleco comes near him. But generally isn't doing it as much anymore (I think he learned a new way to behave). As for the hith I did two sets of general cure treatment ( which contain metronidazole and praziquantel). I simply followed the instructions listed on the box and did a second application 2 weeks later. I believe I found what the underlying stressor was, he absolutely hated the silver dollars. I went ahead and removed them from the tank and relocated them to other tanks in the house. since the end of the two weeks of treatment I've already seen some recovery, almost all of the holes have disappeared completely, except for the big one on his left side. though it is shrinking. Of course I will continue to monitor him. I feel it is also important to note that at no time did I see a my oscar lose his appetite during this as I've read some people have had issues with that (sorry I can't be of more help). I believe that if you find your fish in similar circumstances I recommend you try to figure out what the underlying stressor is, treat your fish, and remove said stressor. If his health begins to degrade again I will also further update this post otherwise he is happy and healthy. As for me this was a very stressful experience and I hope that anyone who finds them in a similar experience the best.

 

[revanblaze]

To me a 20 to 30% water change every 2 weeks is inadequate, and not enough to ward off chronic HITH.
In fact, I would find a 20-30% water change once per week inadequate to ward off HITH, especially with all those other fish in a 180 gal.
In my 180, with heavily planted sump. I try to do at least a 30% water change every other day, with much less stocking than what you appear to have.
Below my heavily planted sump sump
View attachment 1537700.
I know to many that regime might seem excessive.
But since you love that oscar.....you need to get to the root of the problem, and I expect, it's too few, and too small water changes, unless you brought in a new fish without QTing it
If it were me, and I saw the onset of HITH, I'd ramp up my water changes to at least a 50% change per week, and see if that makes a difference over the next month or so.
Since HITH is chronic and takes time to infect, I wouldn' expect to see any change for the better until at least a month has past, and if there is no improvement, I'd work up to say, two 40% water changes per week.

30% water changes every other day is absurd for a 180 gal and unnecessary. I do this same water change regiment for very similarly stocked fish tanks and they are all healthy happy and even breeding. If the underlying issue was unstable water I'd agree, but as I'm pretty sure I stated the aquarium waters parameters were and have been stable. Of course water changes are important and always good, but that very clearly wasn't what was at fault in my post. I think it's nice of you to try and help, but I did ask for peoples advice who've had similar experiences on the matter, not do water changes lol

 

[duanes]

In actuality, where I've spent time in the Cenotes of Mexico, the cichlids are are in constant 100% water change daily because upwelling currents from underground aquifers are strong enough to push me toward the mangrove.
And in Panama where I've been collecting cichlids lately, the rivers provide 100% water change every minute, and the surrounding forest eats nutrients like nitrate as soon as they are produced, and shown by the testing I do wherever I collect.

Compared to nature, the 30% every other day water changes I do are paltry.