Nitrate and nitrite levels

Question
QUESTION: My question is what would cause a drastic increase of the nitrate and
nitrite levels in a matter of a few days? We have a 55 gallon tank which
has been up for four months now. We have been doing a 25% water
change once a month. This past month we have been doing bi-weekly
water changes of 10% and then 5% vacuuming a portion of the gravel
once a week. On Sunday, we did a 10% water change and checked the
levels which were all perfect minus the ammonia (because of our goldfish)
which is why we started bi-weekly water changes. Yesterday, (Thurs.) we
had a dead snail. This morning (Fri.) we had two dead snails and four
dead mollies and the nitrite and nitrate levels have sky rocketed between
Sun. night and Thur. night. What can cause this and how do I fix it? I did
do a 25% water change and vacuum after removing the dead. Any help
would be great. Thank you for your time.


ANSWER: Hi Dawn,

I really need more information.  What kind of filter are you using?

How many goldfish are we talking about and what other fish/inverts are in the aquarium?

My thought is this is caused by a raise in Nitrites, and nitrates...which are poisonous to fish.

ANY detection of nitrite can be a death sentence.

I believe one snail probably perished for unknown (as of yet) reasons, and then the other fish/snails became poisoned by the nitrites in the water.

It is safe to bet the ammonia levels are off the charts as well.

I would suggest the following causes:

Overfeeding, under-filtration without weekly /bi-weekly required filter changes, and/or too many fish in the aquarium, or water quality issues.

Also, I am willing to bet you are using tap water with dechlorinator.  

Please use the distilled five gallon bottles full, and use them for water changes as well.

Right now, I'm going to advise that you take out more than 10%.  I would rather see you remove 40% of the water.  

Replace that with filtered water, from a water station, and then, there is something to remember about goldfish.  One goldfish per 5 gallons.  No more than that.  Never overfeed.

People add chemicals to their tanks believing it's helping, when it's only destroying the natural water that fish like.  Dechlorinator = easy way out, but it is not the best to use.  

Filtered water has proper PH, proper hardness, no chlorine, metals, chloramine, and none of the things that dechlorinator does not remove.

Filtered water is the best idea.  I use water that has gone through an R/O unit (reverse osmosis) and through a Peat canister, rather than simply filtered water.  But, filtered is fine if that's all you can get.  It beats the heck out of tap water.

Overheating can cause snail death as well.  I raise 3 species of snail in my aquarium, therefore I must only have fish that don't go above 72 in my aquarium.  The snails would die.

So, these are of course preliminary ideas.  I do hope they help.

Dawn, please do this also:  Please take specific time to examine all the fish and invertebrates thoroughly tonight.  If you can't find anything physically wrong, then we have to assume this is caused by water quality.  90% of aquarium issues are.

I feel awful for your loss.  I've been there.  It's heart-wrenching.

I hope my preliminary ideas help.  Write back and let me know the specifications of your filter, etc., and we can go further from there, perhaps.

You can always also include an uploaded image of the aquarium and filtration on a photobucket account, linking it in the reply message.

Sincerely,

Renee

---------- FOLLOW-UP ----------

QUESTION: Renee,

Thanks thus far. I agree it was the nitrite and nitrate levels but was most
curios how they changed so drastically to try to prevent from future times
and how to fix. I apologize for not including the fish quantities the first
time which I meant to do and forgot. We are using a Top Fin double filter.
I'm not sure what other info you would need for the filter.
Before the four dead fish we had 1 dalmation molly, 2 white mollies, 1
fancy tail guppy, 2 glow fish,1 mickey, 1 bala shark, 1 goldfish (which we
allowed 12 gallons of tank due to the high ammonia put off), 2 small
loaches ( can't remember the type) and two algae eaters. Oh and our
mollies had babies so we had 3 additional small white mollies. We have
lost all but one white molly and a baby molly. So, in short, what we have
left is a goldfish, 2 algae eaters, 1 mickey, 1 bala shark, 2 mollies, 2
loaches, 1 guppy, 2 glow fish and 1 snail.
I also needed to correct that we do a 15% water change and then a 10%
water change throughout the week.
You had mentioned removing 40% of the water. How many times and
how often? Or would this just be to get the nitrite and nitrate levels back
to normal.
As for the snails when we bought them I tought they needed the same
temp as our fish. We keep the tank at 78 since the info provided to us was
all our fish maintain between 74-82. I unfortunately had to leave town this
morning and won't be able to check on them until tomorrow afternoon. Do
you recommend a 40% water change tomorrow?
Thank you again for your help!

Sincerely,
Dawn

Answer
Hi Dawn,

First of all, the filter is insufficient, even though you have properly allotted gallons of water per breed of fish.  Nice job on the community sizing of the tank vs. fish kept.  Many aquarists seriously overdo the community of fish, per gallon ratio.

I would remove at least 40% of the water, replacing with filtered water, tonight and I'd let that go 3 more days before redoing it again.

I'd just do normal 10% water changes to 25% once a month once this is under control.

I'd also clean the gravel.

Back to the filter - It's a good filter, but like I say in my profile, they're never rated for many aquarium situations and on any 55 gallon, I advise at least 2 double filters, one on each side.

These are the benefits - 1. Flow increased keeps debris from settling.  Airborn debris sucks up the tubes and gets cleaned out of the water, rather than rotting in the gravel.  2. Cleaner water, less ammonia, less nitrates, no nitrites should be present.  3.  Less water changes.  With proper filtration, you can do partials once a month, in most cases.

Your goldfish is a 65 degree fish, to 70 (at most) in order to be comfortable.  Although they can exist at higher temps, they are not as comfortable and can often be seen at the top sucking air when oxygen deprivation due to heat causes them to breathe improperly.

The algae eaters...if they are plecostamous, you can keep them at a lower temp also.  Most aquarists don't realize that these are cooler fish, being comfortable the most around 72.  Also, snails are almost always 70 to 72 degree inverts.

I hope this helps. :)

Good luck and please send an update to let me know if this helped.  Please consider the second filter.  :)

Renee