fresh water fish behavior

Question
my tank has been set up for 2 months
my tank is 46 gallons
fresh water fish
charcol filter
not sure about my levels
i change my water once every 3 weeks
the whole tank goes through the filter 4 times evry hour
my question is how come all my fish are swimming to the top i have 30 fish and a snail and  all are at the very top
be tried putting in some relaxing liquid and the temp is still the same as always but there still all at the top

Answer
Hi Mackenzie;

Breathing at the top is an indication that they are lacking oxygen or there is something burning their gills so they can't absorb oxygen. Make a 25% water change right away. It will lower fish waste toxins in the water in case that's what is bothering them. Be sure to use water conditioner in the new water and be sure the new water is the same temperature as the old water.

If they don't feel better after the water change, get an air pump and air stone to add bubbles to the water.

Next, take a sample of your tank water to your local fish store and ask them to test for the levels of ammonia and nitrite (not nitrAte, it's different and won't cause these symptoms). If either ammonia or nitrite are elevated you will need to make 25% water changes daily until they go down to "zero" and stay there. Your tank is still fairly new and it may be going through the break-in period still. Toxins rise during that time and can be very hard on the fish. It can take up to 8 weeks to complete the break-in period after the first fish are added. Here is a link to my own page about it;

http://www.xanga.com/Expert_Fish_Help

It would be helpful if I had more information about your tank and fish so I can help you find out why your tank is having problems. Here is what I need;

How long have you had fish in the tank?
What kind of fish are they?
How big are the fish?
How much of the tank's water do you change every 3 weeks?
How often do you clean the filter?
Is the filter running properly?
Let me know what the ammonia and nitrite levels are as well...

At Your Service;
Chris Robbins