Nitrites rose

[witch-1]

In one of my tanks - after a 10% water change and water tests (which were all ok)... two days later I noticed 4 of my fish at the top gasping (Tank has been going now for 7wks - fish in it last 2wks)

I checked water again and the nitrites had risen from 0 to 0.25-0.5. I have taken most of the fish - starting with the 4 that were gasping and put them into my other tank (which is far to busy now but for a few days I'm sure they'll cope). Unfortunately I couldn't catch all of the fish, so a few have remained insitu. Strangely no amonia?? and nitrates are around 5-10.

The next day I did a larger water change (about 35%) and now the nitrites have disappeared. I checked again this morning and still 0. Tonight when I return from work I will recheck all tests.

When do you think I can return my fish?

Somehow during all this I have been fortunate (so far) not to lose any fish during this crisis!!

Many thanks
JJ

 

[missileman]

0.25 - 0.5 nitrite shouldn't have caused a major problem with the fish,
What have you got for circulation to help get O2 to the bottom of your tank? Airstone maybe?

 

[CaptainAhab]

Sounds like your tank either didn't fully cycle or there aren't enough beneficial bacteria established to support the addition of 4 fish at one time. Even now that the fish are gone, are you feeding the tank and ammonia source to keep/grow the bacteria?

Feed the tank, test if for the next few days to make sure it's really FULLY cycled. Then add the fish bad 1-2 per week and test.

 

[witch-1]

Many thanks - no I haven't been feeding the tank, so will do. I had been checking water at least twice a week, so was shocked with the little spike!

Hate to admit, but sounds like not cycled properly...

 

[CaptainAhab]

I would lean towards 'fully' and not 'properly'. Patience is always the hardest part.

 

[witch-1]

Just fed the tank - there is still 2 remaining fish in there, but again the nitrites read 0 on my return from work.

Will then start returning their oppo's one at a time, one week at a time.

I thought it had fully cycled saw the amonia's rise, then the nitrites, then the nitrates... then as it sat on amonia & nitrite at 0 for a few days I thought I was there...

 

[CaptainAhab]

It might be as simple as just adding too many fish too fast for the bacteria to adjust to the 'live' levels vrs the levels you were 'feeding'

 

[witch-1]

Think your probably right - I just thought that after a fishless cycle you could near enough stock up fully... my 10 fish was not even close to being fully stocked!

Never mind - many thanks for your support and advice. Shall slow down the process and add as above... just need to keep an eye on other tank now as over stocked while housing the lil extras!