new 125 gallon need help

[fisherman26]

I have a 125 gallon freshwater tank thats been running for a little over a week it has 12 danios and a 3 inch goldfish in it currently.
I put some used filter media from my 10 gallon tank in it to help cycling.
I havent got any ammonia or nitrite readings yet but have 5ppm nitrate. Does this mean that the tank has cycled already?

 

[Daannn]

First off, just to let you know, tropical fish should not be kept with cold-water fish.

If you have added bacteria from your old tank and some of the old water then I would say that the tank may have skipped the Nitrogen Cycle due to bacteria already colonising in the filter.

But do keep checking the water daily with your test kit to make sure. The second you see a rise of Ammonia, do a 20% water change daily until it hits 0ppm. Do not add chemicals to reduce ammonia - this will make it worse and unbalance the natural cycle.

Yet so far, things are looking good. Keep up with 20% water changes and maintaining your filter and you should be fine. Live plants will help!

Best of Luck;

 

[BigJim]

Danios and goldfish are both fine in cold water.

Check your tap water for nitrates. I've seen this situation several times only for the poster to test their tap water and have their hopes dashed by finding nitrates in the tap.

I'd be very skeptical that the tank has cycled already, even if you switched your entire filter from your 10g over.

 

[toddnbecka]

As long as you seeded the tank with filter media it will be cycled, but will take some time for the bacteria to colonize the whole setup.