Tank cycling--constant ammonia + no nitrites?

Question

So I've had my 20g tank set up for about 7+ weeks now. During this time, I've certainly seen ammonia, which I have to constantly battle to keep below 0.25, but I still have no nitrites. Could it be that my bacteria aren't developing? Why? I've got 4 threadfin rainbows and 4 cory cats, along with a few danios and white clouds, in my tank. I do 25% water changes w/ a siphon every couple of days to try and keep the ammonia down. I have two filters, an in-tank whisper 10 and a hob penguin mini, so I've got 30 gallons of filtration. I'm not overfeeding--I feed a small amount every other day. pH is around 7.2, tempertaure is at 75. Right now, ammonia: 0.25 (time for another water change...sigh) nitrite: 0 nitrate: 0. I use Prime water conditioner, and API test kits--drops, not strips.

Why won't my tank cycle properly? I really don't want my fish to suffer from the ammonia.

I did add fish slowly--started out with the danios, added the white clouds, then the rainbows, then the cories. I suppose I can slow down the water changes--would adding Prime daily help combat the ammonia in between? I know it doesn't remove ammonia, just de-toxifies it, so the bacteria would still have food.

Okay, I'll try Prime every day (just did it today) and cut back on the water changes. Hopefully that will work...

To the fourth answerer, it HELPS to add established material to your tank, but you don't NEED to for bacteria to grow. Unfortunately, I don't know anyone else with a fish tank.

Answer 1

I walked a gal through this once before, and it worked for her with only 2 fish dying. Start using the Prime everyday, it only stays active for 24 hours in the water. It'll neutralize the ammonia and eventually the nitrites without removing them so the tank can still cycle. Then only do a weekly water change, about 20% and dont' vacuum the gravel or don't change out the filters. Using the Prime everday will help so you won't have to do the water changes every few days, and like I said, will neutralize the ammonia so it can build up and hopefully let the bacteria get established. But, you will most likely still get ammonia and eventually nitrite readings on the test kit, kind of like a false positive. Just monitor them and see if the nitrites start showing up soon.

Or, even better, if you know someone with an established, disease free tank, you can use some of their filter media or filter "drippings" and put it in your filter to kick start the bacteria.

Answer 2

Yes, those levels are what you would expect for a fish in cycle. Just carry on. If the ammonia or nitrite go higher do a part water change to control them, and keeo on waiting. When the ammonia and nitrite drop back to zero then you have some cycle working and it's safe to add a few more fish. You may not see the nitrate rise much in a planted tank as the plants absorb ammonia, maybe most of what a few small fish like that produce. Ian

Answer 3

It's quite possible that the bacteria are so slow in developing because of the low levels of ammonia. Ammonia and Oxygen are the chemicals that the bacteria use as nutrition. Keeping the Ammonia levels low is actually starving the bacteria. The first colony of bacteria(Nitrosomonas) eat Ammonia and produce toxic Nitrite as waste,obviously you don't have a sufficient colony. When you see the Nitrite numbers begin to rise you will know that the first colony of bacteria is established,then you will have to begin growing the second colony (Nitrobacter) which will live on the Nitrites,and produce Nitrates,which will be easier to manage.
The way to avoid harming your fish or subjecting them to damaging levels of Ammonia is to do fish-less cycling,too late for these fish,but give it some consideration next time you start a tank. If you can find someone that has a filter like one of yours,that has been running in a cycled tank for some time,and you can convince them to let have one of their filter cartridges(say, one the are replacing) then give it a gentle rinse and install it in your tank for about 6 weeks it may give you some relief from the water changes.
With the bio-load that you have in your tank (a light one),your should be able to get by on once a week 20% water changes after the tank cycles. Until then you may have to allow the Ammonia numbers to creep up slightly,to nourish the Nitrosomonas.
I believe that cycling with fish is unnecessary cruelty,perpetrated by fish sales people to sell more fish,and aquaria. How many people would not start an aquarium if they were told "you won't be able to have any fish for several weeks"?
Fishless cycling requires a lot of patience,but it is much more humane.
One last word of caution,your Threadfins will be the first to feel the effects of elevated Ammonia,so watch them very closely.
To sum up what I've written,"The fastest way to cycle a tank is to let the ammonia numbers go way up into the toxic range. This still takes a few weeks to establish good sound colonies. You can not do that with fish in the tank."
I hope this is clear,if not you can e-mail through this forum.

Answer 4

Nitrites need ammonia, so it's possible your constant battling of the ammonia has prevented the nitrities from ever growing. I'd recommend doing water changes less often to allow ammonia to get to a level where nitrites and eventually nitrates will develop. Unfortunately, now that you have fish in your tank, they'll have to go through the cycling process as it happens. So keep a constant eye on your chemical levels to make sure they aren't spiking, but rather raising just a little for the cycling to occur slowly.

You might want to ask your local pet shop if you can buy some gravel from one of their established tanks to get some beneficial bacteria in your tank. Even a couple cups of good gravel would help your tank out.

EDIT: I just wanted to add that even though you can’t do a fishless cycle in your current tank, you can do a fishless cycle in a separate container that can then be used to establish your tank with fish in it. Get a bucket or small tank, put some gravel in it and maybe some plants, and begin a fishless cycle. When this bucket "aquarium" is adequately cycled, transfer everything to your current tank. While this is happening, continue keeping the ammonia low in your current tank. I haven't used used this method before (just thought of it), but it would probably allow you to establish your tank without harming your fish.

Answer 5

have you been doing the steady water chances since you first set the aquarium up? It could be that you havent given the tank time to build bacteria. Make sure you arent changing the filter media yet. Maybe slow down on the water changes a bit. If you keep changing the water at first, it cant build up the bacteria properly because you keep taking it out. it could be that your tank is overstocked and never had the chance to cycle properly. I usually try to start with only a few fish in a tank until it is cycled. then slowly add the others, giving time for the tank to catch up with the new fish waste.

Answer 6

I agree with PeeTee. Without having a remarkable ammonia spike, the nitrosomas don't have an adequate source of nutrients so they aren't flourishing and sparking the start of the cycle. Nitrites are the by-product of the nitrosomas and nitrobacter won't colonize the tank until there is a remarkable nitrite spike. The spikes involved in cycling are very hard on any fish made to endure them. Ammonia literally burns the fish exposed to it and nitrites enter the bloodstream and cause the blood to be unable to carry oxygen to organs. The risk of losing fish is very high when cycling a new tank. This is why fishless cycling is the preferred route when starting tanks.

Answer 7

did you remember to innoculate the tank?
did you add any gravel from an old tank or any filter media, etc?
bacteria can't grow if they aren't there.

you need SOME source of bacteria you can just put fish in water and hope stuff turns out right, that's what they were doing in victorian england, hoping their fish would live more than 2 weeks.

Answer 8

My guess is that you have too many fish for a cycle. You should only have a maximum of 25% of your tanks fish capacity to begin the cycle. I would return some of the fish, (including the cory cats, they're not good cycling fish!) and see if that helps.
Here's a fantastic site on cycling.
http://www.firsttankguide.net/cycle.php
Good luck.

Answer 9

try pushing more air through. the top of the water should be vbery rippled. that's where you get exchange of gases, and can get rid of your ammonia. the rougher the water surface, the better.