Ammonia Poisoning

Question
QUESTION: Hello,
I have a 30 gallon tank set up that has been running for nearly 2 months now. There are 3 bloodfin tetras, 3 zebra danios, 1 sand loach, 1 flagtail catfish, and a pleco. I lost 3 columbian tetras today.The filter broke and it was a few days until I could get a new filter put in so I was doing 50% water changes daily. Now there is a new filter in but I lost the columbian tetras. All of the fish except for the catfish and pleco were gasping for air with purple gills so I removed them and put them into a smaller tank with fresh water.When is it safe to put them back?

Please Help I'm very worried about the fish espically the loach the rest are happier in the smaller tank but it doesn't have a filter or anything.

ANSWER: Hi Susanna,
How do you know they are suffering from ammonia intoxication?  Are you testing it using liquid testing?  A broken filter is not all that bad, there are some aquarists even myself that dont use filters on some tanks.  But that is besides the point.  

During the 2 months that the tank has been running, have you been doing water changes 1-3 times per week?  Especially in a new tank, the necessary beneficial bacteria has not grown and multiplied enough to be able to break down ammonia.  Thats why water changes are needed during the process of "cycling" a tank.  Because of the lack of BB, the tank's ammonia level cannot be broken down fast enough to prevent intoxication.  After a tank has been cycled, you can resume water changes to weekly and bi-weekly.  

It is safe to put the fish back when the Ammonia and Nitrite levels are below 0.50ppm.  Nitrate also must be less than 40ppm.  You can test these levels by using a Liquid Test Kit.  They sell them at mostly at local fish store.  Test Strips are very inaccurate and I suggest not using them.   

The process of cycling is called "Nitrogen Cycle".  There is a lot of information of google about it.  Understanding the Nitrogen cycle gives you a full understanding of the nitrogen levels in tanks that causes poisoning and how to prevent it.  Ask me a follow-up question if you have any questions.  
-Matt-

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

QUESTION: Well,
I haven't tested it yet because the store was closed. I used the bacteria when I first set up the tank and this issue didn't happen until the filter broke. The water is still murky and I'm afraid to put the fish back in the water yet until I test it or do another water change. Will they be alright without the filter in the smaller tank for a couple days? I think I've got the nitrogen cycle understood now. They symptoms they had sounded like Ammonia poisoning, the gasping, purple lungs, lethargic. Could it be that the catfish and pleco are more durrable and that is why they weren't showing symptoms?

~Susanna

Answer
They will be fine as long as its only a few days.  Replace the water every now and then because the water will have toxin build-up and be depleted of oxygen.  New water will replenish both.  Plecos are very hardy and could explain why he was not showing symptoms.  

When you said you used the "bacteria" when you first set up the tank; what bacteria are you talking about?  Where did you get the bacteria?  Normally the only way to get bacteria is from another healthy tank by the filter media, or any item from a mature tank such as plants, driftwood, decorations, or gravel.  The bacteria they sell in stores in a small package do not work and is basically false advertisement.  This is not surprising.  Chain fish stores like petco and petsmart sometimes sell aquatic plants such as ribbon plants, ferns, and umbrella plants that are not... aquatic plants and will die submerged.  They also sell driftwood made from grapevine, which will decay in less than a week and will make your tank smell like rotten eggs.  

Just remember to look out for water quality.  Bad water quality makes fish more susceptible to diseases like ich, fungus, parasites and etc.
-Matt-