Oscars, Cycling, and Cloudy Water

[Meeky]

Hi there!
I set up a new 255L (~67 gallon) tank for my adult oscar about three months ago as I was having unrelated issues with his old one. As it's virtually impossible to acquire clear ammonia where I live, I decided to do a fish-in cycle with six tiger barbs and some filter media from an established tank. After three weeks, the ammonia, nitrites, and nitrates were still at 0, so I figured that the barbs were just too small to cycle a tank that big. I put the oscar in (the tiger barbs 'mysteriously' vanished overnight), and the ammonia levels did rise so I think my assumption about the barbs was correct. I've been keeping the ammonia under 0.5 with twice weekly 30% water changes (occasionally 50%, if necessary) but it's been two and a bit months now and the nitrites and nitrates are still at zero. My oscar is as happy, healthy, and hungry as ever, so I'm not concerned about that; I was just wondering if it's normal for a cycle to take this long? My other tanks only took a matter of weeks...

Also, in the past few weeks the water has begun to cloud and has taken on a slightly greenish/yellowish tint. Advice?

The tank is lightly planted and has a large piece of driftwood if that's relevant. pH is about 6.8.

 

[kno4te]

What's ur filtration (mech and bio)like? Are u adding bacteria to the tank?

 

[Meeky]

I have a 1100 Nautilus Canister Filter, which has got sponges, wool, bio balls, and sintered glass media in it. I use API Quick Start during water changes.

 

[tlindsey]

If you are using API Freshwater test kit shake the Nitrate bottles vigorously for about a minute or so before testing.
If you get positive reading for Nitrates then you may need more bio forr your filter . I suggest don't over feed even if Oscar is begging for food lol.
Welcome aboard

 

[kno4te]

Using a dechlorinator for the water changes? Like tlindsey mentined already.

The discolores water is likely an algae bloom. Reduce feedings and increase water changes to larger than 50%.

 

[Meeky]

Thanks
I did as you said, but nitrates are still 0.

Yes, I dechlorinate during water changes.

Okay, I'll reduce feedings (though my oscar will be heartbroken) and increase water changes, and see if that helps.

 

[tlindsey]

Thanks
I did as you said, but nitrates are still 0.

Yes, I dechlorinate during water changes.

Okay, I'll reduce feedings (though my oscar will be heartbroken) and increase water changes, and see if that helps.

How many times do you feed a day?

 

[Meeky]

How many times do you feed a day?

Once a day, with extra treats once or twice a week.

 

[tlindsey]

Once a day, with extra treats once or twice a week.

Great

 

[skjl47]

After three weeks, the ammonia, nitrites, and nitrates were still at 0

Hello; even with small fish there should be some ammonia produced. Also some ammonia from decay of uneaten food bits. Some live plants are reported to take up ammonia so might reduce it a bit, but this is a small process I think.

barbs were just too small to cycle a tank that big.

Hello; My take on tank size and cycling is that it is the bioload of living animals (mostly fish) and not so much the tank size. The two groups of beneficial bacteria (bb) adjust there colony sizes to the ammonia and nitrites present.

A difference between a small tank and a large tank with the same amount of fish being that the larger will have more water volume in which to dilute things such as toxins like ammonia and nitrites.

With a small bioload (a few small fish) and water changes (WC) the large volume of water may have diluted the nitrites and ammonia enough so the test kit was not sensitive enough to register. However I cannot think of a mechanism of why small fish in a large tank can not set up a cycle. My thinking being the barbs should in fact have set up a cycled tank in time.

Adding an Oscar would change things right away. Oscars are messy eaters and also are reported to make a bigger bioload. That the barbs disappeared seems to indicate the Oscar ate them. Add to this the extra feeding of the Oscar which likely leaves more excess food to decay. This means that the smaller colonies of bb which were possibly not yet even in balance with the barbs could not use all the ammonia from the Oscar and the extra from decay, so a spike of ammonia occurred. In time the bb will multiply to take up the newly increased level of ammonia. Might take a while.

As already stated by others, WC and maybe reduced feeding should help.

The cloudy water may have to do with either the extra feeding or the wood or a bit of both. I think folks who use wood in a tank will soak it an a tub for several months before putting it in a tank. I do not use wood so cannot advise from experience.

good luck

large piece of driftwood