This is the third week my has been set up.
Last week test show ammonia and nitrite readings but today I tested again before water change, it shows no readings in nitrite or nitrate but only ammonia.

Could the cycling process stopped?

Hi Nathan,

A few questions for you, to help us to help you:

What is the size of the tank (litres or gallon)?
What are you using to cycle the tank?
What filtration do you have?
What's the PH in the tank?
Have you seen any nitrate readings at all and how high have ammonia and nitrite gone so far?
What is the reason for doing a water change at this stage?

Thanks for reply FL,

I'm not doing fishless cycle, it's the 90L tank with danios, cherry shrimps and hillstream loaches. No casualty so far.

pH is 7.5, I'm using internal filter. I do water change daily.

Highest ammonia was 0.50 ppm, I don't remmeber the exaclt number for nitrite but it was normal. I haven't seen any nitrate reading (or I can't tell). Nitrate test show dark yellow but I still think it's 0 as it's now as dark as the lowest on the chart.

I'm doing daily 20% water change

This is the problem unfortunately when cycling with fish. The whole cycling process takes much longer because of the (essential) water changes.

You should be testing daily at the moment though to ensure the water stays safe for the fish, and remember, with fish in the tank the only reading that can be classed as "normal" for nitrite is "0".

Keep a close eye on those HSL - an uncycled tank is particularly risky for them (and shrimp).

I see, so the cycling process just got back to the beginning?

Thanks, I'm keeping a close watch on them.
THe only problem is hsls are really picky and accept spinach only when they hungry, otherwise they prefer to have the sinking pellet

The cycle probably hasn't gone back to the beginning, it's just a very slow process when done with fish. Apart from the risk to fish by using them to cycle, that's another reason to do fishless cycles. They are more controlled, easier to monitor and faster. Even a fishless cycle can take 4-6 weeks; fish in takes longer.

If the HSLs are happy eating pellets then don't worry. As long as they are eating they will be fine in that regard. However, as they can be sensitive to unstable tank conditions they are at risk while the tank cycles so do test daily and keep ammonia and nitrite at a minimum.

ammonia and nitrite will never goes past 0.50ppm.

I didn't mean to do this, I was rushing to rehome the bettas in an unsuitable bowl to a suitable home (which was a 60l old home of danios and shrimps). The new tank suppose to be instant cycle as I used old filter media but my dad wash it in tap water without noticing me I only discover dad a day after buying hsls

It's worth remembering for the future that while adding some media from an establihed tank may help start the cycle, you will not get an instantly cycled tank capable of supporting full stock levels from that.

The only time old media can produce an instant cycle is if all of it is transferred and the tank is stocked with the same number and sizes of fish - only practical when upgrading though as you can't take all the media out of a tank that will still have fish in it.

Thanks FL
I was really careless

The amount of media I took was very small compare to the media/stock left in the 200l

Well, never mind - you'll know for next time. As long as you monitor carefully and do water changes to keep toxins low the fish stand a good chance. Live and learn, as they say