Fish Cycling Help

[jumblepod]

hey im new to fish keeping apart from a few goldfish years ago. Now im trying to have a ago at keeping tropical fish.
I currently have a 35L tank which like an idiot i went and brought fish for before i new about cycling properly. I was just wondering how long does a tank take to cycle with fish in it. In my tank i have 1 gourami(there was more but they died in the first week). Its now day 20 and ammonia is at 0.1 and nitrite is like 3mg/l which is very high. i was wondering how long you reckon it will take before the nitrite starts falling. btw the gourami is very happy and doesnt look stressed at all.

 

[Corleone]

Cycling with fish can take longer than fishless cycling because to protect the fish, since nitrite and nitrate are kept low and not allowed to spike out of control like in a fishless cycle. It still takes in the range of a month to six weeks, depending on how many fish you have through it, and right at the end of it, you can't increase stocking as you can with a fishless cycle or you risk a mini-cycle.

You'll want to start doing water changes and get nitrite and ammonia (which shouldn't be an issue anymore by the sounds of it) under 0.25, and then keep them there. Even if you're not recognizing signs of stress, they're likely there. Nitrite reduces the blood's ability to carry oxygen, effectively suffocating them no matter how hard they pump their gills. Because it's so high, you might want to start doing small (10%) water changes every hour or two to bring it down. I don't know the all specifics of shock, but fish in very bad water can die of shock when they get too much clean water too quickly.

The water changes won't slow the cycle - in fact, there was a thread recently where Dr. Hovanec (who's researched aquarium bacteria quite extensively) posted that the ideal growth for the nitrite processing bacteria in aquariums is at around 0.14 mg/l nitrite.

Also: It sounds like you've been testing regularly, what was your water change regimen through the cycle so far?

 

[jumblepod]

Thanks for your reply. I have been testing my tank right from the first week everyday. Initially in the first week the readings were ammoina 1.2 and nirite was 0.1. in the second week everything changed ammonia decreased to what it is now 0.1 and nitrite went up a great deal to like 4.0 and it hasnt shifted since im now on day 20 i really dont know wut a good next move would be. I heard when nitrite starts to come down it does it quickly is that right? i really dont know wut to do. o yeh ive been changin the water like twice a week. 20% changes.

 

[waterdrop]

Yes, you need to be more active in varying the frequency and/or percentages of water changes (always with conditioner and ideally with rough temperature matching unless the percentage is small.)

You make these adjustments to your water change schedule based on how well you are able to keep both ammonia and nitrite as close to zero as possible. You want to test at least daily and ideally morning and evening. You want to acheive levels between zero and 0.25ppm for either poison, ammonia or nitrite. You need to be using a good liquid-reagent test kit for these numbers in order to trust them.

It is correct, I believe, to expect this process to take 4 or 6 weeks unless you are pretty lucky. What will happen is that one or the other amount will want to creep up on you (probably nitrite at this stage, as you've mentioned.) Eventually you will measure and find that the filter by itself has kept things at zero and you won't have to do a water change. If this happens again the next day then this is a very good sign. You should still test heavily for the next week, confirming that the filter is doing the job by itself.

At all times your goal is to keep those levels down between zero and 0.25 as that is what the fish need. Don't worry about the bacteria getting enough food, or about how long it will take. This is your only option, which makes it easier anyway.

~~waterdrop~~

 

[OldMan47]

Right now, Jumblepod, I would switch to a daily regimen of a 30% change. If things are not much better after 2 or 3 days of this, try 30% morning and evening. Your remaining fish are presently paying the price of you waiting to see what happens. What ends up happening is the fish die if you don't take action.
This will not slow your cycle in any way. If you think about it, you are trying to grow enough bacteria to handle all of the nitrites coming through the cycle. As long as there is any build up at all of nitrites, there is more than enough to feed whatever bacteria there are at the moment . This means get a healthy level for the fish and the cycle will take care of itself.

 

[jumblepod]

ok what ive done is done water changes every 1-2 hours i now have my nirites down to 0.3 should i take this any lower or will it affect the bacteria growing?

 

[Corleone]

Take it lower, but you're getting there - low enough that it doesn't get over .25 between water changes. It won't hurt your bacteria growth as much as higher will hurt your fish, and Nitrispira grow best in very low nitrite levels. At this point, I'd just do one big (~50%) change instead of staggered small changes, and continue doing similar daily.

 

[Miss Wiggle]

do as many changes of whatever size and frequency is needed to keep both ammonia and nitrite under 0.25ppm

if you can get them down to 0 then do so.

the best practical advice is to not worry over the bacteria being fed but worry over the welfare of the fish, the bacteria will take care of themselves the fish won't.

 

[jumblepod]

ok got my nitrites down 0.25 just need to wait now and see if they rise again.

 

[OldMan47]

Your can expect the nitrites to rise again so don't be surprised if you are changing water again tomorrow.

 

[jumblepod]

been 2 days now and no rise in nitrites there still under 0.25.

 

[Miss Wiggle]

good, that indicates you are quite far on in your cycle otherwise it would be rising quicker than that, just keep monitoring and if it pops up above 0.25ppm then do some more water changes.

It's worth noting though that while we say keep it below 0.25ppm that doesn't mean that 0.25ppm is safe, so if you can get it lower or down to 0 then you should do so, so i'd be doing daily water changes anyway to keep it as low as possible.

the 0.25ppm is like a maximum it should be at, if you can get lower then do so, 0 is obviously the ideal.