My tank had started to cycled and I dont know why!

I noticed the problem yesterday when I saw the otto's in the tank swimming freely during the day and I thought it looked slightly odd. On closer inspection I found that there was one dead otto in the bottom of the tank with the rest all swimming in a drunk fashion (best I can explain it) around the tank and not acting ottoish at all.

I quickly checked the water to find that both my ammonia and nitrite where off the chart. My yest kit only measures to 3.3mg/l for nitrite and 7.3 mg/l for ammonia and both were at max (highly toxic). I quickly did a 75% water change (this was about 2 oclock in the afternoon). I figured that as the bacteria in the filter must be having a problem I swapped all the filter media from my Rio 180 into the filter box of the rekord 70. After the water change I check the water again and it was at 1.6mg/l for nitrite and 4.9 mg/l for ammonia. I figured that as the media from the 180 was completely mature it wouldn't have a problem handling the NH4 and NO2.

I checked the water again in the evening and it had gone back up so I carried out another 50%. I check the water again this morning and it was reading roughly the same as the night before. I thought it strange that it hadn't reduced at all. I didn't have time to do a water change this morning. After work this evening I checked the water stats again and they both had gone back up to the maximum, the same as the previous day. One more dead otto and the rest gone back to their funky swimming patterns. I carried out nearly a complete water change this evening and this reduced the nitrite to 0.3mg/l and ammonia to 1.2 mg/l. I have also added an additional internal filter with more mature media. Here is hoping that this will do some good.

I have no idea why this has happened. The tank has been running for nearly a year and was fishless cycled at the beginning. I am always very careful to ensure that I do not over clean the media during filter maintenance. What is also puzzling is the fact that the media from the other tank (three weeks since it was cleaned) had no effect on the level of nitrite and ammonia and that in-fact they increased. I do not over feed so where is all the ammonia and nitrite coming from? There are no dead fish in the tank and all food is eaten at the time of feeding. Also to my knowledge there was no power outage as all my other tanks are fine.

So I have some question!

What can cause a tank to loose its nitrifying bacteria?

What else can I do to reduce nitrites and ammonia? (I have just used seachem prime this evening, apparently it breaks down toxic levels of nitrites)

Will ottos recover from ammonia/nitrite poisoning or are them doomed once there hemoglobin has been effected?

Where would the excess ammonia be coming from? Could it be from old fine root hairs from plants I removed left in the substrate?

Tank details

70l
Temp 23/24C
Water changes 30% every week
Fish: 5 ottos (was seven), 2 black moores, 1 ranchu.
plants: yes
plant ferts: Kent Pro plant, kent Freshwater plant
Co2: Yeast Co2 Reactor (home made job)
NH3= 1.2 mg/l
NO2=0.3 mg/l
NO3= <5mg/l

Any ideas of info would be greatly appreciated

regards

Denis

Have you checked your tap water for ammonia.
Stop feeding the fish until you get it down. Use Safe water by King british I use it all the time.
Sodium chloride can stop nitrite entering the bloodstream of fish but not so sure your ottos will like salt. Do you mean Ottocinclus cats.
I don`t think they will recover from such a high lever of Ammonia but you never know.

Keep up the water changes and adding the bacteria. Don`t feed them either. Keep us posted.

Hey Anthony

thanks for the fast reply. I should have been more specific regarding the fish they are indeed the oto catfish . Otocinclus affinis. As for the salt I do remember reading somewhere that you cant use salt with them, but I will do a quick check and report back.

As for my tap water. I checked everything and the only thing to show was nitrates at less than 5mg/l.

So for the moment I will keep up the water changes and testing the water. I don't know if I'm going to be able to get my hands on safe water within the next few days as I've got a lot of pancakes to eat tomorrow. Plus I think Seachem prim does a similar job.

Thanks for the input and I will keep you posted.

regards

edit: fish had stopped being fed as of two days ago.

denis

I would disconnect Co2 system,
bacteria in filter could be dead
also have heard about ph crashes using these
It may not be this but i would disconnect for day or so just to eliminate

Hi Denis,
are you missing any fish. Could be a dead one somewhere. Once I had two neons trapped behind the internal filter in a Rio 180 and it took me a while to find them


Holger

Hi Denis,
are you missing any fish. Could be a dead one somewhere. Once I had two neons trapped behind the internal filter in a Rio 180 and it took me a while to find them


Holger

Exactly why I tore that poxy enclosure out of my Rio 240.
A seperate internal is much neater and easier to clean imo.

I would disconnect Co2 system,
bacteria in filter could be dead

I'm sure that it is not the Co2 system as it produces so little Co2 that the effects would be negligible (also its coming to the end of the sugar so its not really catalysing) but as you said it would be a good way to rule it out.

The concern that I have is that even if the bacteria in the filter was dead I replaced it all with mature media from another tank which should have taken care of the problem

are you missing any fish. Could be a dead one somewhere. Once I had two neons trapped behind the internal filter in a Rio 180 and it took me a while to find them

All of the fish are present an accounted for! Except another otto that was dead this morning!

Update:
I checked the water again this morning, the ammonia has dropped by half but the nitrite has nearly trebled. I expected this based on the ammonia turning into nitrite. Hopefully the seachem prime will prevent this from getting to a toxic level.It just seems so bizarre that there should have been such a high level of ammonia in the water and that even the media I changed from my other tank wasn't able to handle the excess amount!

NH3= 0.6 mg/l
NO2=0.8 mg/l


I'm out of ideas so I will just keep up the constant water changes and water monitoring.

I asked this above but I will try again!
Recently I removed two large swords from the tank. They both have large rooting systems and had interconnected under the substrate with the stricta and other plant. When I was removing them I cut the finer interconnected roots off leaving them in the substrate as I didn't want to disturb the other plants. Could these decaying roots be causing the high levels of ammonia?

I would go for a full clean out and leave nothing to chance.At least you will be in control of the situation and can have peace of mind that everything has been done.

potentially yes. If you poke your finger into the substrate where the swors used to be, do you get any gas escaping from the substrate?

I would go for a full clean out and leave nothing to chance.At least you will be in control of the situation and can have peace of mind that everything has been done.

I would like to try and avoid a complete tank clean out as it would remove all the money I pumped into the root tabs and substrate fertilizers. Plus it would involve me removing all the plants and I would like to try and avoid this as it would undo a lot of hard work of trying to get plants established in the presence of goldfish, which is an absolute nightmare :shock: :shock: .

potentially yes. If you poke your finger into the substrate where the swors used to be, do you get any gas escaping from the substrate?

I do a small amount of gravel vacing along the surface of the substrate but not to deep as this would remove the substrate ferts. Saying that the layer of gravel itself is not more that 1.5-2 inches deep (maximum). But I will check for anaerobic gases later and will post the results. Should I be looking for large amounts of bubbles or would just small amounts of tiny bubbles be enough to cause a problem.

Speaking of the problem! what is the direct result of a build up of anaerobic gases in a substrate? and how can it effect the level of ammonia and nitrite in a tank?

Thanks for the input so far guys!

a partially anaerobic substrate is actually good for plants. makes it easier to take up certain nutrients such as iron. If the amount of anaerobic gases in the substrate is too high you'll be heading for trouble. If you see bubbles escaping from the substrate you'll clearly have too much of a good thing

I agree with Chrism.
A fresh start id needed.
Start by doing 2x 50% water changes over 2 days. Ammonia kills filther bacteria in high doses. I forgot this yesterday When you have done this add some bacteria from your existind tank. Just squeeze the pads straight into your new filther. This should do the trick.
Add the Safe water when you get it each day for a week.
These chemicals you but to remove ammonia can be useless. Some are temporary and some just desquise the readings
Add an airstone to your tank to help with disapathing the ammonia.


Start feeding the fish a little after the 100% change. The bacteria added from your old tank should do the trick. If you are going to the meeting let me know and I will bring something for you.

Thought I would post and finish this thread!

With the addition of mature media and an extra filter, I was able to get both the ammonia and nitrite back down to zero. The nitrates are also non existent with the amount of water changes that have taken place within the last two weeks. (I avoided a complete clean out)

I still have no idea why the tank cycled! It just did! I lost two fish in the process but nothing major! This will remind me to check my water stats more often as it must have taken some time for the ammonia to reach such a dangerous level.

As for the otto's. The remaining five are still with me and are feeding and look healthy. But their behaviour has changed completely they are now free swimming fish and are far more active although their swimming is highly erratic. So, like Anthony suggests, Ammonia poisoning in otto's is irreversible. I will keep you posted on how long they last.

Regards

Denis