Nitrite And Nitrate

[gtigaz]

hello im new to fish keeping, i introduced myself to the forum about 4 weeks ago, i set my tank up with a sand base and both live and plastic plants also i put a bubbling shipwreck in which i think looks quite good i decided to go with the fish in cycling as it seemed the easier option as the section i read about fishless just went over my head, its a 250 litre tank ive got 5 male guppies, 4 platies, 5 zebra danios, 2 silver sharks and 2 clown loach (was 3 but 1 died night before last but never showed its face from the start and looked very thin compared to the others) other than that all seems fine and happy, so my question, i took a water sample to be tested about a week ago and all was fine then afew days later had it retested and the nitrite was quite high the bloke in the shop said to do 10% water changes everyday, so ive done 2 changes yesterday and the day before but dont really want to do anymore because of the bacteria i will lose, now i did a test myself tonight to see how it is doingand the readings i got was nitrite 4 looking through the tube sideways and nitrate 50 looking down the tube, is the nitrate kicking in to kill the nitrite now or am i in trouble?
 
thanks
gaz

 

[fluttermoth]

You won't lose any bacteria by doing water changes. The bacteria stick, quite strongly, to whatever you have in your filter; that's how you can clean your filter media in old tank water without washing all the bacteria off.
 
You need to do much larger water changes to get that nitrite level down; anything over 0.25PPM is toxic to fish.
 
I think you might have misunderstood the nitrogen cycle a little bit. Nitrate doesn't kill the nitrite; what happens is, during your cycle, you'll get bacteria growing that eat the ammonia produced by the fish and turn it into nitrite. Then, later, you get another family of bacteria that eat nitrite and turn it into nitrate.
 
You need to keep testing and water changing to keep both ammonia and nitrite as near to zero as you can possibly manage; your filter will still cycle with levels of ammonia and nitrite that are to small to show up on our home test kits.
 
Try and change at least 95% of the water right now; leave just enough water for the fish to swim upright (don't forget to switch your heater/filter off first!) before refiling with warmed, dechlorinated water.
 
Don't forget that, in the wild, fish that look or act sick are soon targeted by predators, so fish often won't show symptoms of being sick, even if they are.
 
Just to top off the bad news, while we're about it, I'm afraid both the silver sharks and the clown loach are going to outgrow your tank, and should probably be rehomed or returned to the shop as soon as possible.

 

[TwoTankAmin]

The proper initial stocking to fishlessly cycle that tank is 5 zebra danios. Can you take the rest back? The clowns are at the greatest risk.

 

[gtigaz]

right thanks for the info seems ive misunderstood the cycling part then, Il have to leave it until tomorrow now for the water change tho as getting late now, ive just been looking at the tank and everyone seems energetic, the loach normally come out about now to, will keep it posted thanks again

gaz

 

[b3cca]

I recently did an unintentional fish in cycle, with way less bioload than you - 3 harlequin rasbora but in a lot smaller (70 litre) set up and was having to do 2 partial water changes every day just to keep my ammonia at a safe level.
 
I was testing my ammonia and nitrite levels 3 times a day to keep on top of things.  Spikes can happen anytime so i would advise getting your own testing kit as you can take water to the store for testing but by the time you get home your parameters could have easily shot way up.
 
Only Took me about 4 weeks even with doing 2-3 part water changes to fully cycle it , so water changes obviously didn't affect the cycle at all and all my fish are still alive and happy.
 
4 ppm nitrite is horrible,  google "brown blood disease" to see what painful and cruel damage it is doing to the poor fish

 

[the_lock_man]

B3cca is right. Nitrite enters the blood stream and oxydises the haemoglobin in the blood. The resulting chemical is not able to transport blood around the fish's body, hence brown blood disease. Effectively it suffocates the fish.
 
If you were to tie a plastic bag over your cat's head, and thus deprive it of oxygen, you would be prosecuted by the RSPCA (or your local equivalent), and rightly so. You're doing the self-same thing to your fish.

 

[gtigaz]

right ive done a 50% water change today and the fish are already alot more energetic so i think Il do a 25% change tomorrow and Saturday aswell so that will be 100% then go get a test and post up the results, thanks again for the advice, fingers crossed

gaz

 

[fluttermoth]

Ah, mate....
 
The thing with doing smaller water changes is; you're not doing 100%.
 
If you do a 25% change tomorrow, then only 12.5% will be of your toxic water; the other 12.5% will be the new water that went in today.
 
if you have any reading for either ammonia, or nitrite, then you need to do a big water change; if your nitrite is at 4PPM, doing a 50% change will only bring it down to 2PPM; which is still eight times as high as it should be.
 
You need to get it to below 0.25PPM ASAP. I know you say your fish look better, but as was said upthread, sick fish will often not show any symptoms at all.
 
These 50%, 25% water changes are just not big enough.

 

[gtigaz]

hmm Ino what your saying mate, so what would you recommend taking the full 95% out in one so as not to mix the original tank water with the new?

 

[fluttermoth]

Yes, I would,
 
Just make sure your new water is properly temperature matched, and properly dechlorinated, and add it fairly slowly, giving time for the fish to adjust. Oh, and don't forget to switch your heater/filter off first!
 
That should get your nitrite down to a more acceptable level

 

[gtigaz]

right ive done that i did it in a 10 litre bucket put the dechlorinator first so it was properly mixed and used the kettle and thermometer to get the temperature right so Il leave it a few hours and go get a water test and post up the new results , fingers crossed

gaz

 

[fluttermoth]

Let's hope things have improved

 

[gtigaz]

got the water tested and the nitrite is down to 0.5 so a big improvement, been told to do a few 10% water changes now for a few days is that right?

 

[Essjay]

A nitrite of 0.5 is still too high. You need to do another big water change asap like you have already done. Anything smaller will still leave a nitrite level that is too high. You need to get it down to well below 0.25.
 
The person that told you 10% a day is far too cautious. You should not be doing a set amount every day, you should be testing for both ammonia and nitrite at least twice a day and doing water changes as often and as big as necessary to keep them both well below 0.25. The frequency and amount should be guided by your readings. Just under 0.25? Do a water change. Over 0.25? Do a big water change. A lot over 0.25? Do a very big water change. The idea is to stop either ammonia or nitrite ever getting higher than 0.25. Getting it to just that level means it will have gone over it by the next test so each water change should get the reading as near to zero as possible.
 
Edited for spelling

 

[fluttermoth]

I just want to say that essjay's advice is 100% right.
 
Follow that and you won't go far wrong