6 Dead In 24 Hours!

[Haveagojoe]

As the title says I have lost 6 harlequin rasboras in the last 24 hours, I noticed yesterday that things didn't look right in the tank loss of appetite and general lethargy in all the fish and then one by one the harlequins started dropping away, they just started swimming erratically and seemed to struggle to keep alive.
I did a quick 50% water change and upped the airation but this morning the last two in the shoal were dead.
I took a sample of water to my lfs which incidentally is very good they seem to be very knowledgable, they didn't give me any figures but said the ph was ok but the nitrate was a bit high and ammonia was a tiny bit above what it should be, but because I had done a large water change I had probably diluted it and the readings the night before would have been a lot higher.
Ive done another 20% change today and the fish seem to have picked up a bit but they still are not feeding, I was wondering what would cause this,have I over fed, I feed twice a day with flake and cat pellets but when I gravel vacced today I noticed an awful lot of un eat pellets in the gravel, would this cause the high nitrate reading?
Also why have only the harlequins died, they have been in there about 6 months now and they were the last additions to the tank.
Should I continue with the water changes say every other day or go back to my routine of 20% weekly or maybe alter it to 10% twice weekly.
It is a 120ltr tank fully planted running yeast co2 Fluval u3 filter cleaned monthly in tank water with 25 fish mainly small inhabitants.

 

[SensesFail]

As the title says I have lost 6 harlequin rasboras in the last 24 hours, I noticed yesterday that things didn't look right in the tank loss of appetite and general lethargy in all the fish and then one by one the harlequins started dropping away, they just started swimming erratically and seemed to struggle to keep alive.
I did a quick 50% water change and upped the airation but this morning the last two in the shoal were dead.
I took a sample of water to my lfs which incidentally is very good they seem to be very knowledgable, they didn't give me any figures but said the ph was ok but the nitrate was a bit high and ammonia was a tiny bit above what it should be, but because I had done a large water change I had probably diluted it and the readings the night before would have been a lot higher.
Ive done another 20% change today and the fish seem to have picked up a bit but they still are not feeding, I was wondering what would cause this,have I over fed, I feed twice a day with flake and cat pellets but when I gravel vacced today I noticed an awful lot of un eat pellets in the gravel, would this cause the high nitrate reading?
Also why have only the harlequins died, they have been in there about 6 months now and they were the last additions to the tank.
Should I continue with the water changes say every other day or go back to my routine of 20% weekly or maybe alter it to 10% twice weekly.
It is a 120ltr tank fully planted running yeast co2 Fluval u3 filter cleaned monthly in tank water with 25 fish mainly small inhabitants.

Did you cycle the tank before adding the stock?

Have you got a testkit to test the readings?

 

[star4]

Dont feed for 24 hours and do a small daily or every other day wc to remove all uneaten food until they start eating again. Personally try some brine shrimp & garlic to help them get their appetite back again. You may been to increase your wc to 30% a week or 2 15% changes if the 20% has not been enough.

 

[Haveagojoe]

Help another 3 have gone,pencil fish.

 

[star4]

Thats with a 50% wc change this morning? I would do another wc now or in the morning. Have you had any aerosols sprayed in the room with the tank? air fresheners etc, have you done a full head count there isnt another fish died somewhere you havnt found? just to check your tank hasnt been contaminated. Give the gravel a good vaccing make sure no "air" is trapped anywhere.

 

[notg2009]

your tank is 6 months old, so the bio filter should have been developed by now, unless you have changed something drastically lately, ie filter change, gravel change, water temp, etc. maybe there is a viral/bacterial/fungal infection going on. Have you examined the dead fish for spots, or any other irregularities? You've had these fish for more than 6 months so whatever happened is something pretty new. I don't think water changes can help that much if there is an outbreak of a deadly disease that can kill fish in such short period of time. Maybe setting up a temp tank is a good idea, while you empty and clean your main tank, but that's just what I think is right.

Anyone correct me if I'm wrong

Good luck

 

[Haveagojoe]

What a disaster of a day its been I,ve lost nearly all my fish! all thats left is a german ram 6 pencil fish and a cory, I don't have another tank to isolate them, so I did another big water change today and have left the lights off all day and the survivors seem to be ok.
Whats gone on? nothing has been added to the tank we don't use sprays in the house its got be baffled!
I noticed on the zebra danios that their gills seemed really red and inflammed but that was the only noticable indication on any of the dead fish, could that be a sign of an ammonia spike but the tests showed that the ammonia wasn't high and with the water changes I have done over the last few days surely if it was that it would have come down.
How would a viral infection get in the tank I have not put anything new in there, I just can't get my head round this one its as if they were poisened or something for them all to go so fast I am absolutly gutted!
Do you think the filter will need recycling or with water changes whatever got in there will be removed, I am not adding fish for at least a month or so I want to see how the remaining ones do.

 

[elisew]

Sorry to hear you`ve lost some of your fish.

The red gills could possibly be down to the ammonia which could have been at a high level before you did your water change, but unless you have your own testing kit you won`t be able to know how high the reading is at any time or how much water you`ll need to change to bring the levels back to normal. Can you get yourself a liquid test kit?
I know it`s not always financially viable for everyone but bearing in mind the cost of the fish when they have to be replaced a test kit of your own could prove to be less costly

As long as you leave the filter media alone the water changes shouldn`t affect it.

 

[divetime84]

sorry to hear about the losses what a week.
i have just got a test kit of ebay liquid one for less than £20 with p+p have a look if you are local you can use mine if you want

john

 

[Haveagojoe]

sorry to hear about the losses what a week.
i have just got a test kit of ebay liquid one for less than £20 with p+p have a look if you are local you can use mine if you want

john


Cheers m8 where are you, I'm in Liverpool on the blue side!
Just an update on the tank,I've put the survivors in a small tank I aquired and completley redone the tank, cleaned the whole thing out, the only thing I hav'nt cleaned is the filter, so I am starting again I really don't know what else to do Its a complete mystery to me and yes I will have to get a liquid test kit, could you pass on a link to where you got it or email me,I will put my addy on the profile page.

 

[JasonandJill]

I know it's too late to be of any help, but Is it possible that you forgot to dehlorinate some water during a change? Obviously some bacteria would have been killed off, explaining the possible ammonia cause of the red gills. Your next water change which was then tested would have "diluted" the results.
I've been distracted before and come close to putting straight tap water into the tank.
Doesn't help now but may explain it.
All the best

 

[anon02]

Could you have gassed the fish with co2