Hi Nitrate and Dead Fish

Hi all,

I've only been a fish keeper for 4 months but mad into it now and my Cichlid tank is coming on great, or at least it was until I went on holiday a few weeks ago.

I left a digital feeder set to deliver just the right amount of food twice a day, 9am and 7pm. A 'helpful' friend who was house sitting while we were away misunderstood when I said the fish were automatically being fed morning and night and thought I was asking her to feed them morning and night whilst we were away. You can imagine the amount of food they got being fed 4 times a day for two weeks, a full container of food which would normally last 6 weeks at least had been fed to them in two weeks.

Fortunatley none were dead although most of them looked seriously bloated!! I immediately took away their food for a few days, did a 50% water change and cleaned out all the waste that had accumulated at the bottom of the tank.

Since then I've noticed each week when I do a water change that Nitrate is reading 40 wiwth Ammonia 0, Nitrite 0 and PH 8. It doesn't seem to matter whether I do a water change 2 days or two weeks later the readings are still the same and although I was a little worried that Nitrate always seemed to be high I didn't think it was doing any harm until last night when a previously healthy looking fish died.

Can anyone shed any light on this? Is 40 Nitrate with 0 Ammonia and 0 Nitrite a common set of readings for a stablised tank and the fish just died and would have likely died anyway or is the high Nitrate likely to have been the cause and thus the rest of the tank is also at risk?

Has anyone any suggestions other than daily water changes?

Regards,

Ben

Ben,

What were the readings of NitrAte before the holiday?

keeping up water changes will help you a lot.. your filter is playing catch up at the moment as its bio load had a dramatic increase..

feed normally as a mature filter will adjust.. the water changes are the best you can do.. NitrAte at 40 is ok on short term exposure but long term will stress and damage your fish..

I would change water with 50% prepared water every day until you see the drop in NitrAtes.. (when i say prepared, i mean heated, aged water) also monitor any Ammonia and NitrIte spikes over the next weeks..

unless you see any other fish heading down hill keep that going.. IMO

Adam,

Thanks for the advice. I don't have the ability to prepare 200l of water in advance but will do more frequent water changes and hopefully things will revert to normal levels.

What should I expect Nitrate levels to be over the long term? They were usually around 20 after a week prior to going on holiday.

Regards,

Ben

Ben would you mind giving me a list of fish kept and equipment used.. maybe even a photo or 2.. and 20 is fine.. anything between 0-30 is ok but IMO 30 is too high.

The more info i have the better chance of helping..

Adam,

I have a 1500mm long x 500mm wide x 600mm high 450L tank sitting on a purpose built cabinet. It's got a Tetra Tec Ex 1200 External filter and a 400 U. V. sterilizer, a Tetra Tec 300 w heater, T 5 Lighting unit and Coral sand and rock (70 kg's). You can see a picture and pictures of some of the fish at this link www.irishfishkeepers.com/cms/component/o...imit,10/limitstart,0

Have about 34 fish now. 29 Malawi Cichlids of the various sorts in the pictures, 3 Tangs I'm not sure the names of and two juvenille rusty Plecos.

I guess something must be going well as we've had two instances of 'holding' and currently there are 3 fry hiding out amonsgt the rock. There also seems to be another one of the orange guys holding at the moment and I'm taking that as a good sign that conditions are usually OK in the tank.

I know I should use the proper names for them but I just can't get my head around the formal names!!

Ben