Help - No2 Levels

[JamieP]

Hi all,
after having a tank for a over 6 weeks, i finally got my NO2 levels down to 0, confirmed by my own tester kit and from a shop (gave them a water sample), so i added in a couple more fish to my setup, as i assumed it was safe!

I added the fish in on saturday...

i added in a gold nugget pleco (£30!!), male fighter and angle fish.
Within 8 hours the pleco was dead (!) and my NO2 levels had gone back up to over 1 if not more!
Ive since down 3 water changes (25%) yet the water is still high NO2 and i cant work out why its suddently all gone from being good to shocking?!

help please! sorry!

other info if helpful....

my NO3 is still at 0.

Im running a Rekord 600 with 4 neon tetras, red tailed shark and 2 zebra loachs, plus the male fighter and angle now.

 

[JamieP]

also, the fish are all at the top of the tank trying to take in air from the surface?!?
so ive added in an air stone, if thats what they need?

 

[coldcazzie]

Fish will be at the surface because (if I am right) NO2 is nitrite and nitrite acts like carbon monoxide to fish - they are suffocating. (although please someone correct me if Im wrong!) You need to do one or more much larger water changes to bring nitrite down to 0, and asap.

What is your ammonia reading at?

Or do you mean that your ammonia (NH3) has spiked, but your nitrite (NO2) is still at 0? In which case the answer is you put too many fish in at once and it caused an ammonia spike.

 

[JamieP]

Fish will be at the surface because (if I am right) NO2 is nitrite and nitrite acts like carbon monoxide to fish - they are suffocating. (although please someone correct me if Im wrong!) You need to do one or more much larger water changes to bring nitrite down to 0, and asap.

What is your ammonia reading at?

Or do you mean that your ammonia (NH3) has spiked, but your nitrite (NO2) is still at 0? In which case the answer is you put too many fish in at once and it caused an ammonia spike.

hey, thanks, that helps
its the NO2 thats high (Nitrite) and the NO3 (Nitrate) is fine.
since adding in the air they have all stopped gasping and i did another water change.
ive got some more water warming to room temp now, so will bang that in, in the morning too and see how its going

 

[jmkgreen]

You have been adding ammonia on a regular basis, right? Not one dose then wait?

If you've been following the fishless cycle and can add 5ppm of ammonia then see ammonia and nitrites rise then fall to nil inside of 12 hours then you really ought to be ready. How big is the tank and what is the filter?

 

[JamieP]

You have been adding ammonia on a regular basis, right? Not one dose then wait?

If you've been following the fishless cycle and can add 5ppm of ammonia then see ammonia and nitrites rise then fall to nil inside of 12 hours then you really ought to be ready. How big is the tank and what is the filter?

hi
i didnt know i was meant to add ammonia? i thought that came from the fish?


Rekord 600
Decor: Black
Volume: approx. 63 Litres
Measurements: 61 x 31 x 42 cm
Productcode: 21600

 

[OldMan47]

The ammonia in your tank does come from the fish. We use the fishless method more often to cycle a tank and JMKGreen just got confused. Do not add any ammonia to a fish-in cycle like yours. Rather than worry about adding an air stone, do big water changes and get your nitrites under control. Cazzie is quite correct about nitrites affecting fish the way CO affects people. No matter how much oxygen there is, the nitrite will prevent them getting enough oxygen by binding too tightly to the fish's hemoglobin and making it difficult for the fish to use the oxygen that is present. You need to get the nitrites under 0.25 ppm and keep it there.

 

[JamieP]

The ammonia in your tank does come from the fish. We use the fishless method more often to cycle a tank and JMKGreen just got confused. Do not add any ammonia to a fish-in cycle like yours. Rather than worry about adding an air stone, do big water changes and get your nitrites under control. Cazzie is quite correct about nitrites affecting fish the way CO affects people. No matter how much oxygen there is, the nitrite will prevent them getting enough oxygen by binding too tightly to the fish's hemoglobin and making it difficult for the fish to use the oxygen that is present. You need to get the nitrites under 0.25 ppm and keep it there.

thanks for the info

rather then doing a large 50% change, could i do a 25%in hte morning then another 25% in the evening, for a few days?

 

[JamieP]

ive done 2 changes of of 75% water in the last 2 days and the levels are still really high...any reason why this would happen when the levels were at 0?

 

[coldcazzie]

The levels will remain high until the bacteria grow enough to be able to consume that amount of nitrite. Unfortunately that means you have to keep changing the water daily until the levels drop to 0 and stay at 0 by themselves. My recent mini-cycle took 8 days of daily water changes. I know it sucks, but it's better that than dead fish...

 

[JamieP]

The levels will remain high until the bacteria grow enough to be able to consume that amount of nitrite. Unfortunately that means you have to keep changing the water daily until the levels drop to 0 and stay at 0 by themselves. My recent mini-cycle took 8 days of daily water changes. I know it sucks, but it's better that than dead fish...

thanks, i will do!
i just dont get how it goes from being "0" right up to really bad, when i only added in a couple of fish

 

[coldcazzie]

Seems the tiniest thing can set it off sometimes. Maybe it was the combination of the three that was the killer - maybe adding 1 a week would have worked, maybe not? I have no idea... but now you're here you can only do what's necessary to keep your remaining fish from dying! and next time maybe add a single fish at a time and then monitor closely.

 

[OldMan47]

If you have done a fish-in cycle, you don't have much of a bacterial colony, especially when it first gets to zero on ammonia and nitrites. By adding a rather large biological load, you have greatly increased the need to process ammonia and nitrites but have done nothing to allow the bacteria to develop. Now that you are in the middle of things, about all you can do is big water changes until the bacterial colony develops some more. Once things settle down, give it some time and make the moves up in stock levels small compared to what you already have in the tank. The time between moves needs to be plenty long enough to allow the bacteria to respond and settle back down. A full week is not really long at all for that.