Wiped out my fish in 1 water change...

Had a terrible weekend because I decided to clean my canister filter and do a 40% water change, which resulted in the death of all of my Malawi Cichlids except my male N.venustus. I thought that the hardy cichlids would be able to cope but I was very wrong!

Im not 100% sure what actually killed them but I think it was maybe the temperature difference. I was devastated and felt helpless and it was a very hard lesson to learn. Hopefully it will never happen again!

 

Temp diff could have done it....Question - did you dechlorinate the water?

 

Temp shock happened to me a while back, tap water is freezing atm.

 

That's why i am reluctant to clean my filter .

 

Sorry about the losses mate!
Perhaps alternate with doing water change or filter clean....can be a double whammy....

 

Depends, if the fish started dying right away then its temp shock / chloramine / chlorine and if they start dying after a few day then it could be your filrter bacteria that was wiped out.

You are far worse of not cleaning your filter and its starts blocking and the bacteria do not get enough O2 and also start dying.

 

Hi, not nice to hear.

How did you clean your filter?

 

This sounds horribly wrong! How can fish die from cleaning your filter? And all that over the weekend? Must be something else. I know our municipality spike our tap water with chlorine over weekends. It is so strong, you can smell it coming out of the tap. Water temp? Then it must have been a huge difference to act so quickly? Did you not bring the temp up at all?

I will be shocked if this was indeed caused by cleaning the filter. I think it has nothing to do with it. Even if you wiped out your bacteria, the effect will not be as fast. What is your bio-load like? Overstocked a lot?

 

Cleaing a filter out will not wipe out your fish....unless you cleaned it with Handy Andy....

 

Oh no, so sorry to hear about your losses. Please give us a little more details about what you did by way of cleaning your filter and what type of water you used by way of temps and such so that we can maybe help you to figure out what went wrong...

 

My sympathies, thats not a good feeling at all.

I think you would help other fish keepers if you can shed some light as to when the fish started to show signs of stress, straight away after the clean, or a few days after?

 

Sorry to hear about your loose man it really is a crappy feeling I know it happened to me a while ago as well

 

Oh Bummer! Thats enough reason to make any weekend crappy! Sorry to hear about the losses

 

Thanks everyone. It's a 600l aquarium which had 35 Malawi Haps all 1 year old. I have done weekly water changes of around 20% and they have always been fine. The water was looking a little yellow so I decided to do a 40% water change and clean the filter which i don't do very often at all. It was at 22*C and after the water change it went to 18*C which I didn't think would have any major effect, 3hours later when I went to check on them most were dead or dying. I spent several hours trying to revive them in my other tank as a last resort but only my biggest male survived. I didn't add any dechlorinator because I never do and they are always looking healthy after previous water changes... Im pretty bleak as you can imagine

I cleaned the filter by running the filter media under tap water which I knew would kill the bacteria but I added bacteria during the water change in hope of replacing them over time

 

ALLWAYS add dechlorinator.... that is what killed the fish - even a 10% change without declhlor can kill.... Gauteng water gets treated with more clorine/chloramine in winter especially cos the dams are so full of algae with no rainfall....

 

@azurekoi Well now I know :/ Thanks for the insight as it will probably save many of my fish in the future.

@Reedfish Thanks, yeah I agree. I wish I had known! Its the worst feeling ever, losing all your fish that you have cared for for so long, I got them all as colourless juveniles! I don't even feel like keeping fish anymore :sad2:

 

don't give up dude!

You've learnt a hard lesson - don't feel alone - me... I capped an existing mess of mixed gravel with riversand - thereby wiping out a good proportion of the baccies in my substrate - lost a few too many fishies till I figured it out and added some bacteria-in-a-bottle. Learn from the mistake, sure, but carry on. :driver: sorry for your loss!

 

sorry mate about you loss hope you will recover soon

 

I always stick my hand in the water to get a "feel" for the temp, then as I refill I feel the water to match it to the tank temp by adding cold or hot water from the tap, and also regularly check the thermo as I'm filling, works every time.