Are Nitrates Poisionous To Fish?

[Annagh]

I have a large tank that I have been cycling (forever it seems) and now it's finally cycled, YAY! I'm worried about doing a 75% water change before I put fish in there. I have plants in the tank, will they soak up the nitrates? Are nitrates harmful to fish? When can I put my fish in there?

Cheers,
Excited in anticipation,
Annagh

 

[Darkehorse]

I have a large tank that I have been cycling (forever it seems) and now it's finally cycled, YAY! I'm worried about doing a 75% water change before I put fish in there. I have plants in the tank, will they soak up the nitrates? Are nitrates harmful to fish? When can I put my fish in there?

Cheers,
Excited in anticipation,
Annagh

If your ammonia and nitrites are zero, you can start adding fish now. Nitrates are removed by doing water changes. Nitrates are poisonous to fish, but they have to be at much higher levels than nitrite and ammonia. Usually nitrate levels of below 20 PPM are considered safe. I personally like to keep mine at no more than 5 PPM, at which point I do a water change. 75% water changes before putting in fish is perfectly fine. This initial water change helps reduce nitrate levels that were created during the cycling process and is pretty much the norm.

Hope this helps,
-Darke

 

[Annagh]

Thanks Darke,

I'll do that today and start shopping for fish.

YAY

Annagh

 

[rdd1952]

Actually, you could do a 100% water change if you wanted. The bacteria you have developed are on the filter media, not in the water. The sole reason for doing the big water change after a fishless cycle is to get rid of the nitrates. But don't do the water change until the day before you get ready to get fish. You will need to continue adding ammonia to keep the bacteria fed. if you do the water change now and don't get fish for 4 or 5 days, the nitrates will begin to build back up. Change the water the night before and dose 2 to 4 ppm of ammonia again. It should be gone by the next morning and you will be ready to put in the fish.

 

[andywg]

Usually nitrate levels of below 20 PPM are considered safe. I personally like to keep mine at no more than 5 PPM, at which point I do a water change.

This is a bit extreme. Scientific tests indicate anything below 100ppm is fine (even in the long term). Many people have 40ppm or more coming from the tap.

 

[dirtydog]

yeah I can get no lower than 20-25ppm really

 

[Darkehorse]

Usually nitrate levels of below 20 PPM are considered safe. I personally like to keep mine at no more than 5 PPM, at which point I do a water change.

This is a bit extreme. Scientific tests indicate anything below 100ppm is fine (even in the long term). Many people have 40ppm or more coming from the tap.

Right, just my personal preference. I usually do weekly water changes, but sometimes I get lazy. My Nitrates are zero out of the tap, if they get up to 5, I know It's been too long and I need to do a water change. Again, just my personal preference. Also I've read that some especially sensitive fish don't do well with high nitrate levels. Why take the risk if you don't have to?

-Darke

 

[andywg]

Why take the risk if you don't have to?

Indeed, but why give the impression that they need to be below 20ppm to be safe when the actual level is 5 times that?

There's no need to scare people into thinking they can't keep fish becauase their tap water has 40ppm nitrates. As an example of fish that tolerate this, CFC has tap water often in the 40s and above, yet keeps rays perfectly well.

There are some fish which appear to have problems when the nitrates rise somewhat, but I can think of no fish that a beginner is going to start stocking a new tank with that will not tolerate 100ppm.

 

[martyn21uk]

Usually nitrate levels of below 20 PPM are considered safe. I personally like to keep mine at no more than 5 PPM, at which point I do a water change.

This is a bit extreme. Scientific tests indicate anything below 100ppm is fine (even in the long term). Many people have 40ppm or more coming from the tap.

Glad somebody came in with that, I can only get down to 20 due to tap water and do pwc at 40.

 

[Darkehorse]

Why take the risk if you don't have to?

Indeed, but why give the impression that they need to be below 20ppm to be safe when the actual level is 5 times that?

There's no need to scare people into thinking they can't keep fish becauase their tap water has 40ppm nitrates. As an example of fish that tolerate this, CFC has tap water often in the 40s and above, yet keeps rays perfectly well.

There are some fish which appear to have problems when the nitrates rise somewhat, but I can think of no fish that a beginner is going to start stocking a new tank with that will not tolerate 100ppm.

True that.

 

[Annagh]

Thanks everyone for all your information. I'll do a water change the day before I get the fish and will watch my nitrates.

Cheers,

Annagh

 

[WILDER]

Only when it get to about 100 then it starts to get harmful.

 

[Danno]

I have a large tank that I have been cycling (forever it seems) and now it's finally cycled, YAY! I'm worried about doing a 75% water change before I put fish in there. I have plants in the tank, will they soak up the nitrates? Are nitrates harmful to fish? When can I put my fish in there?

Cheers,
Excited in anticipation,
Annagh

If your ammonia and nitrites are zero, you can start adding fish now. Nitrates are removed by doing water changes. Nitrates are poisonous to fish, but they have to be at much higher levels than nitrite and ammonia. Usually nitrate levels of below 20 PPM are considered safe. I personally like to keep mine at no more than 5 PPM, at which point I do a water change. 75% water changes before putting in fish is perfectly fine. This initial water change helps reduce nitrate levels that were created during the cycling process and is pretty much the norm.

Hope this helps,
-Darke

75% water change sounds a bit much. I would suggest 10% if you parimeters are fine and if it is during your scheduled weekly matenance.

 

[Darkehorse]

75% water change sounds a bit much. I would suggest 10% if you parimeters are fine and if it is during your scheduled weekly matenance.

We're not talking about weekly maintenance, we're talking about the water change after the cycling process has complete, right before you add fish.

-Darke

 

[Danno]

I would still say 75% is too much. Max 25% to me.