Having Problem

[Tambiyon]

Hi there

I have an 2 & half feet planted tank, recently I have change my top filter to Atman external filter.
About 2 days later all my big fish died only the small one alive.

Please advise me why it is so?

My external Filter is three tier, below level has lava stone substrate, 2nd level - becteria tubes and top level is sponge.

I have even change my outlet tube above the water but still after sometime the big fishes are raising above to breathe.

Pls help me!!!

[dorothy]

did you change the water? or just the filter alone?

[|squee|]

There are 2 possible reasons I can think of:

1) You changed the filter, and didn't transfer the old filter media into the new one. This effectively removes the BB in the filter from your tank, and ammonia is no longer being converted into nitrite. Thus the deaths.

2) The filter wasn't washed, some toxic chemical remains were present.

[Tambiyon]

I did change the water and put adequate anti-cholorine.

[Simon]

did you rinse the filter before using?

[Tambiyon]

Yes, I did. But to no good.
Now I'am running with both filters and the fish looks fine.

How to use ony one filter - External Filter.
If the outlet dip into the water, does it means not much oxygen supply?

I'm presently monitoring!!!

[Simon]

ok, perhaps you can do this, cut some filter media from your existing filter and dump into your new external cannister. If you suspect your fishes not getting sufficient O2, you can move the rainbar slightly above the water line. thats provided, the problem lies in that area. Did you do anything differently? added some new fishes before it happen?

[vinz]

What is the fish load and how much plants do you have? Is it a high-light/CO2 tank?

Your fish are coming to surface to breathe for possible 2 reasons.
1) Not enough oxygen.
2) Ammonia or nitrite poisoning which effect the ability of the gills to function, and absorb oxygen.

!1) Can only happen if you have too many fishes or the plants are not producing enough oxygen. By removing the overhead filter, you also removed the water turbulence that was helping to oxygenate the water (which I think you already know).

(2) Happens if your new filter is not mature enough, so by itself, it cannot process the ammonia and nitrites fast enough and the excess ammonia and nitrites are posioning your fishes.

I strongly suspect it's (2). So as suggested by the others, get some of your old filter media and put it in your new filter. Sicne you are running both filters now, reduce the amount of filter media in your old filter by about 20% every 1 or 2 days. What you remove from the old filter, will result in additional food for the bacteria in your new filter, allowing that colony to grow.

Once you remove the last of the media from the old filter, you can shut it down and remove it.

If you want to play safe with the oxygen levels, get a rain bar for your new fitler and position the rain bar about 1 inch below the water surface. Point the raindar to push the water parallel to the water surface. This will encourage gaseous exchange, but note you will also lose CO2 faster and water will evaporate faster.

I really doubt oxygen is the problem if you have a normal fish-load and a decent number plants.

[Tambiyon]

Dear friends,

Thank You for your advise, will do as suggested and minitor the fishes!

Thanks again for your assistance and advice.

[loneranger]

try provide more oxygen