Hey i have a 180ltr tank and very new to keeping oscars but have loved them since i was a kid, i still have to have more filtration but ammonia levels are very high the tank has only been running for almost two weeks and am very keen on keeping everything as close to perfect as possible. I wasnt given to much information on tank setup and so forth but the shop has been a good help. So far i've been doing a fair bit of research on oscars but am still having no luck with ammonia levels, the p.h levels are pretty much neutral still have to check nitrate. Any form of help i can get from anyone will be much appreciated. I am on a pretty tight budget but will spend what i need to, to make things right for my fish, just very worried about ammonia levels.

When you set your tank up, was everything new? And it has only been running 2 weeks?

it was an old tank given to me i cleaned everything as best as i could but was given some wrong advice so now dont know what to do. Maybe water change but was told that would be bad due to biological matter trying build up again.

OK, it sounds like you are going to have to cycle the tank and filter... In this case you need to do a 30% water change EVERYDAY until your water readings are right. Do you have a water test kit?

It takes about 40 days to cycle a tank, during this time DO NOT clean your filter.

I hope this helps... And if possible do a water change now.

thankyou will give it a go.

sorry yeah got test kits exept nitrate one.

Can you test the water and please post the EXACT readings. Thanks

Hi woldog

Nikisue is spot on

If your tank has been running for 2 weeks then its currently establishing your biological filtration. This process takes around 6 weeks or so and during it you get a ammonia spike, followed by a nirtrite spike, then a reading of nitrate and 0 ammonia and 0 nitrite at at the end.


2 weeks in your situation with ammonia sounds about right. If you have your fish in there I would get some PRIME for the ammonia and nitrite, its supposed to make them non-toxic to the fish. The 30% Water changes will help keep your reading low for the duration of the cycle.

After the cycle water changes will be dictated by your nitrate reading. Generally when this reaches 10 most of us would do a water change which works out to b around once a week.

here is an article you might want to read if you havent already.

www.oscarfishlover.com/how-to-cycle-a-tank
good luck

thanks heaps guys also using chemieze aswell and have added a few live plants aswell.

okey...slow down.... let us sort the things:
1) what the present condition of your fish? is it gasping or breathing heavily?
2) what is feeding regiment and what kind of feeds?
3) what type of filter do have have? capacity? media set up?

since your fish is already there, what we can do is help you cope with the situation;
save the fish, and cycle the tank as well.

Sounds like your tank is cycling, as nickisue said you need to do daily water changes until ammonia and nitrite are zero, also as said add some prime

the important tests to have are ammonia, nitrite and nitrate. Ammonia and nitrite should be zero (this will take several weeks as you are cycling) and nitrate needs to be below 40

Test every couple day, you will see ammonia rise and then fall, and then nitrite rise and fall. Then test weekly before a water change and if nitrate goes above 40, you are either feeding too much or not doing big enough water changes.

G'day the fish seem to be doing really well the first filter was underwater and 500ltr per hr just added a second at 600ltr an hour at opposite ends seems to be doing the trick just taking the time to cycle tank properly is what im concentrating on. I have two oscars 1 long fin albino and one normal not sure what breed but their only babies at 3 inches at moment and two algal eaters. They get fed a freeze pellet once a day for both changing from beef heart and mostly complete cichlid protein pellet. They both seem to be thriving at the moment since new filtration was added but still waiting to see if ammonia is still high on the next test, there was some gasping but that has all gone and their hungry as anything.