I'm having an issue with my oscar, past few days something is wrong and he has been floating on his side for much of the day up at the top of the tank. but then I will come back into the room and he will be swimming around like normal just a little slower. Also, his eyes seem like they are bulging out somewhat. I have cycled the water twice last week thinking poor water quality. I still haven't picked up a test kit yet but I was just wondering if there is something I need to treat him for before he dies.

First thing you you need to do is a water test and give us the readings, exactly, not just it's okay. We need a ammonia, nitrite, nitrate and pH. I am puzzled when you say you cycle the water twice last week, does this mean you did a water change? If so, can you run through how you did it. What about your filtration, did you clean that at all?

Until we know the answers to these questions, it really is virtually impossible to help you.

When you say cycle the water i assume you mean you did water changes. How long have you had the oscar in that tank and did you cycle it, see 'How to cycle a tank' in the menu

You really should get a test kit especially for nitrate but also for ammonia and nitrite

In the mean time, I think you might have a bacterial problem. It sounds like you oscar is getting pop-eye. I had this with a jaguar once and his eyes bulged out and went cloudy. I treated it with Myxazin and it cured the problem. I would do a large water change before treating. And dont worry if it takes a while to cure your oscar. It took 2 weeks for my jaguar to get to a state where he could see - 2 weeks without food!!!!

Another cause of pop-eye can be fighting(the aggressive fish manages to 'hit' the eye causing swelling but usually its only one eye), this might explain the floating on side at the top, he is trying to get away from an aggressive fish? Is your oscar on his own or is there other fish. What are they and does one seem to be aggressive to your oscar

Yea, I meant I did a water change. I have a siphon vacuum and I will clean all the junk off the bottom and typically fill up my bucket two or three times doing this (its about a 4 gallon bucket). As for the filtration, I have penguin bio wheel filter and I replace the filter about once every two weeks or so, but when I change the water I will pull it out and run it under tap water to clean it up a little bit if needed.

Yea I will definitely go out and buy a test kit and let you guys know what I find. Also, this guy does have a tank to himself, the pleco died a couple weeks ago so it's not an issue of fighting another fish. Also, might be a fluke but I didn't feed him today and he seemed to be doing fine today, well I fed him a few pellets tonight and he started acting up again as he started eating them....maybe I need to vary his diet a little better as well?

I dont know much about bio wheels however what do you mean replace the filter or do you mean clean??? Only clean them in tank water that you have taken out during a water change(the chlorine in tap water kills the helpful bacteria that live in the wheel). When you are cleaning the rest of the filter drop the wheel into to the tank (otherwise the helpful bacteria might die)

The fact that you lost the plec and now are having trouble with the oscar is probably linked. Get the test kit asap and post the results

A varied diet is a good idea with oscars but i think your 1st priority should be your oscars health

Ok, so I ordered a test kit and it finally arrived today. I tested the water about noon today and here is what I found..

ph - 8.2
Ammonia - between .25 and .50ppm
NO2 - between 0 and .25ppm
NO3 - about 40ppm


My oscar still is having issues, although not as bad, but something is still wrong. Anything set off the alarm from these readings?

Your pH is really high for an Oscar. When the pH is off many fish (cichilds especially) will start acting very strangely. It can also have a serious effect on a fish's immune system. I've never dealt with Pop-eye, but I know from experience that bacterial infections will take hold easier in poor pH situations.

Also, Ammonia and Nitrite need to be zero. It also couldn't hurt to get your Nitrates lowered. I know that a lot of the folks on this board want to see the Nitrates (NO3) less than 20, but there isn't any real reason for you current reading to be the cause of your troubles. Basically, all of your biological readings are high, they are however within the boundaries of what your fish can handle on a short term. (no more than a couple of weeks)

So... How long has this tank been setup? This is important because a biowheel filter takes months (4-12) to fully build up it's bacterial colony. You said you had a Penguin. The Penguins I've used don't have a spraybar that turns the wheel, instead they are slightly submerged in the outbound flow to the waterfall. That setup takes longer to mature than when the wheel is above the waterfall and turned by a spraybar. Take a look at your biowheel. It should look fairly disgusting. (An Brown/Amber sort of scummy color) If it's still the grayish color that it was when it came out of the box, then you can't yet rely on it to take care of the Ammonia and Nitrite in the tank. Even if it's in good shape, doing too many water changes without properly dechlorinating the water will totally kill off the bacteria within it. Don't just fill the tank with tap water and then put in you dechlorinator either. It takes only seconds for the chlorine to do it's work. Add your product to the tap water beforehand and mix it good, then let it stand for a while. Never clean your biowheel and never let your biowheel dry out. Biowheels are super efficient at eliminating fish waste. But they only work if you give them the time they need to setup, and you leave them alone. If you biowheel is mature then you can clean any part of the filter that you want with tap water. (with the obvious exception of the wheel of course) If it isn't mature, don't clean the filter at all, unless it's so dirty that it isn't flowing properly.

Here is a couple mature biowheels.



This is an immature biowheel. It's two months old.




As for your pH... Your water likely has a high KH (carbonate hardness) as well. These two readings go hand in hand. The easiest way to lower both of these is a product called Acid Buffer by Seachem. Using it is more of an art than a science. However, it converts KH directly into CO2 which will lower your pH. If you are going to use this, don't do it all at once. You Oscar is hurting from something and a sudden drop in pH could cause enough stress to kill it! Try to take it down 0.2 per day at the quickest. Acid Buffer works like a champ so don't get carried away with it. I'd be willing to bet that when you get the pH down your Oscar will start perking up. How did your pH get so high anyway? Is your tap water that high? Do you have limestone gravel or decorations? Figure out what is causing that and correct it. Preventing these issues is much esaier than dealing with them once you've already got a problem.

You have got quite serious water problems. What makes matters worse is that the ammonia is more toxic with very high pH. If I was you, I would go out and get some prime as soon as you can. This detoxifies ammonia and nitrite. I'm not surprised the Oscar is acting strange, he is living in some very dangerous conditions.

Remind me of how big this Oscar is and how big your tank is? Also, how much and how often do you feed your Oscar. At the momen I think you should be feeding him every other day, and only sparingly, this will reduce the amount of waste that goes into the water. You should follow the procedure of cycling a brand new tank. The fact that you have nitrates present is puzzling. If indeed you are doing a test correctly, there is obviously a correct bacteria present for dealing with ammonia and nitrite. Normally, you would have zero readings of these in your nitrate levels start getting high. However, if your tank is overstocked, or if you are putting too much food in and it's not being eaten, you can often get an ammonia buildup.

Also, observe the Oscar's breathing, is he constantly opening and closing his mouth? If he is, this is a sign that not all is right. Sometimes they don't because of lack of oxygen, other times they do it because of too much ammonia or nitrite. He also may be sitting just under the surface more than usual, or hanging around where the water comes back into the tank from the filtration. These are all signs that things aren't quite right in the aquarium

Without seeing it personally, a lot of us are just guessing. Keep us informed of the situation. Like I said, I would advise you to get some prime.

I wouldnt worry about high PH. Stability is the key. As long as the PH of your tank water is the same as your tap water. If it is different you got to find the cause. Try taking any rocks out and let them dry. Put some vinegar on them, if they fizz dont put them back

I live in a high PH area, plenty of limescale round taps. My PH tester which i bought for my discus tank only goes up to 7.6 and my oscar tank maxed it yet people keep oscars round here just fine using tap water

I think you problem is the fact that your ammonia (NH3/NH4) and your NO2 are not zero. This could be because of overfeeding, cleaning you wheel in tap water, not using a dechlorinator when doing water changes or because your tank is new

Overfeeding - When you oscar is well, feed him once a day (this applies for o's 3in and up) and only what he will eat in 3 mins. Uneaten food must be taken out. He will beg for food all the time - dont give in!!!!!

Cleaning the wheel - Follow MNeilssen instruction for cleaning the wheel

If your tank is new then you need to cycle it.

Whatever the reason you have to get the NH3 and NO2 to zero. You can add prime like OFL said. This will help. As well as that you have a choice. Dont do anymore water changes and wait for the NH3 and NO2 get to zero, however you will probably lose your oscar. I would do 20% water changes a day and either feed your oscar every other day or feed him every day sparingly. This way will take longer to cycle your tank but will not expose your oscar to high levels of NH3 and NO2 which will give him a chance. Keep doing this until the NH3 and NO2 are zero. Your will hopefully be better by then

As far as I understand it prime converts NH3 to a safe version but it will still show up on your NH3 test as have ammonia(is this right OFL?). If you add prime then you will only know things are good in your tank when the NO2 is zero

Then you have to get in a routine of weekly water changes, regular filter cleaning and not overfeeding your fish. I would also recommend regular testing of the water

The ph is a little worrying at the moment because of the high ammonia. However, if you can get the ammonia to Zero, the ph will be okay. An Oscar will be perfectly okay with that. Keeping it stable isn't always that easy. Depending on what your ph is naturally, the ph may drop if you have no plants or anything in the tank, remember that fish waste lowers ph. Having lots of plants in the tank can raise your ph. The ph in my tank is 6.0 whereas my tap water is nearer 7.0, no plants at all.. the ph of my small 20 gallon tank that has lots of plants 7.0. Ph can be a pain, however, it's not so vital in tropical Freshwater as it is in marine so don't alarm yourself too much if all the other water readings are good.

I have never had a problem with PH. Its either been high out of my tap or low and needing raising from my RO machine


I edited my last post- does prime convert Ammonia to a different safe form but it will still show up as ammonia on test????