All My Fish Have Died?!

[Minstrel]

I don't really understand what has been going on in my tank, its 240L tank which has been running for nearly 2 years with no massive problems - yes we lost fish but it was one every so often but not like this - but I have come home and all my fish are dead.
We did have an ammonia spike last Monday and over a week we have lost a few fish but we had done 60% water change and then kept taking out between 30 and 45L a day (2 or 3 buckets and our bucket is 15L) we tested yesterday and the ammonia had calmed right down to 2ppm but we didn't want to keep doing more running the risk of stressing them out, I now don't know what to do as I have come home to the whole tank either dying or dead. A lot but not all look like their eyes have gone cloudy and look a bit pulled apart, the very few that are still living look rather like they will be dead very quickly. I don't know what to do or what this could be? We run 2 filters and an air pump so it cannot be oxygen.
I cannot understand for the life of me what has happened, all the water added in was treated and to be honest this has been such a blow I am considering selling my tank if I cannot find and fix the cause.
Please please can someone help me?

 

[laurac94]

Have you done anything with your filters? Like change the media? Rinse it under the tap? What it/was your stocking?

Have you done anything new like add plants, fish, decorations?
Temperature?

 

[Lillefishy]

It sounds like ammonia poisoning, any ammonia is toxic to fish.
Yours is still way way too high, you should do an almost 100% change to get it down followed by another large one if it isn't zero or thereabouts.

 

[snazy]

and the ammonia had calmed right down to 2ppm but we didn't want to keep doing more running the risk of stressing them out, I now don't know what to do as I have come home to the whole tank either dying or dead
 

 
Not sure what has caused the spike, however, doing water changes without briging the ammonia level down to 0 is a waste of time because the fish will die in 2ppm ammonia as fast as in 4ppm or 8ppm. The point is, do a 90% water change and then daily as big water changes as needed to bring the levels down to below 0.25 until the tank cycles again.
 
Regardless of whether you are gonna sell the tank or not, I hope the fish will be taken care of properly prior to that until the current problem is solved. Check the Ph of the water as the tank maybe suffering from "old tank sydrome" where the Ph drops to 6 or below, which affects the filter bacteria negatively and causes a tank crash. This is due to high organic level build up, too much debris in the substrate that wasn't siphoned out, low oxygen content as a result too, and the filter may not be coping with the grown up fish well enough. Also, if the tank temperature has risen because of warmer weather it maybe contributing to the problem too.

 

[ech0o]

Yes, your fish died of ammonia poisoning.  Even less than 1ppm is dangerous.  Your tank should effectively be at 0ppm ammonia/nitrite otherwise something is wrong with how your filtration is working.  It sounds to me like you should be doing water changes more often, and well cleaning the substrate and tank for any leftover food debri or fish waste.   You currently need to do close to 100% (the 90% suggested would be fine) water change, try to match the water temperature going back into the tank, and literally leave just enough for the fish to swim around still.   

 

[Minstrel]

Have you done anything with your filters? Like change the media? Rinse it under the tap? What it/was your stocking?
Have you done anything new like add plants, fish, decorations?
Temperature?

Will answer questions in order.
No not changed the media for a few weeks and when we have we have halved the sponge that was there and added in the new one then a couple of weeks later we have removed the old as we have done for the past couple of years.
Never has the filter media been put under the tap it has always been washed in old tank water.
My stocking was 2 angels, 3 gouramis, (I had heard after I got them that they don't always got on but for 2 years they have been fine together), 1 royal plec, 1 bristlenose plec, 2 featherfin catfish, a bunch of corys (I don't know how many about 10) 6 columbian tetras, and a pit bull plec.

This has been the stocking for quite a long time now, currently still looking very alive are the gouramis, the angels are struggling but are still alive one swimming more then the other, one catfish has outlasted the other but he doesn't look well, a couple of corys look like they are still alive but all else are dead. What do I do? Do I stand a chance of saving any? I obviously cannot do a 100% water change only having one tank. We are going to try another water change to try and save the ones left. I just want to try and save some. If they last a month I will get more, if they die I think I am done with tanks.

 

[laurac94]

Yep I would just do the water change, just make sure the temp is good and the water is dechlorinated before it goes in the tank, if you get the problem under control quickly your fish should recover. I would do more than a 60% though, unless you do a 60% then another 50% immediately after, the fresh water from the tap will be fine, you dont need more than one tank for the water, don't touch your filters either, you need all the bacteria you can get ;-)
Good luck.

 

[Minstrel]

and the ammonia had calmed right down to 2ppm but we didn't want to keep doing more running the risk of stressing them out, I now don't know what to do as I have come home to the whole tank either dying or dead

 
Not sure what has caused the spike, however, doing water changes without briging the ammonia level down to 0 is a waste of time because the fish will die in 2ppm ammonia as fast as in 4ppm or 8ppm. The point is, do a 90% water change and then daily as big water changes as needed to bring the levels down to below 0.25 until the tank cycles again.
 
Regardless of whether you are gonna sell the tank or not, I hope the fish will be taken care of properly prior to that until the current problem is solved. Check the Ph of the water as the tank maybe suffering from "old tank sydrome" where the Ph drops to 6 or below, which affects the filter bacteria negatively and causes a tank crash. This is due to high organic level build up, too much debris in the substrate that wasn't siphoned out, low oxygen content as a result too, and the filter may not be coping with the grown up fish well enough. Also, if the tank temperature has risen because of warmer weather it maybe contributing to the problem too.

I use PH7 and we do a 25-40% water change on nearly a weekly basis (bearing in mind if we are away we cannot do it). We also use stress coat alongside proper ph7. We are boiling a kettle per 15L of water its really the best we can do to get the water closest temp, which is what we do weekly. As per the filters our tank is actually over filtered as we have a large Eheim external and the largest Eheim internal, both are created to cope with larger tanks then we have according to the boxes. I have the windows open constantly and the temperature inside my house is quite cool, of course there is also a thermometer which is currently reading about 26/27. We are trying everything we can I was more distressed when I thought all was dead but I am just hoping I can save some. After losing my horse of 12 years this is the last thing I wanted to deal with, nearly all my beloved fish gone

 

[Minstrel]

To try and do it all as fast as possible we are changing 50% and then another 50% straight after as obviously we cannot do a 100% in one go. Is this good enough?

 

[laurac94]

That should be around a 75% water change, do this, turn everything back on and leave the tank for about 30 mins, then test again.
Are you cleaning the gravel thoroughly too? Give it a good shake around and all of the rubbish will come out of it for you to suck up. Gravel vacuums work well to a certain extent but not brilliant. If your ammonia level is still above 0.5 then I would do another 50%, might take alot of effort but hopefully it will work ;-)

 

[Minstrel]

That should be around a 75% water change, do this, turn everything back on and leave the tank for about 30 mins, then test again.
Are you cleaning the gravel thoroughly too? Give it a good shake around and all of the rubbish will come out of it for you to suck up. Gravel vacuums work well to a certain extent but not brilliant. If your ammonia level is still above 0.5 then I would do another 50%, might take alot of effort but hopefully it will work ;-)

We have silica sand so we hoover over the top as the hoover (siphon) takes up the sand as well. Okay will leave husband doing this, he has filled it up just 10% off the top and is now going to take out another 60% he says which equals the same another 50%. Okay so under 0.5ppm is okay? Will test now and see how we are going mid way through!

 

[stanleo]

Just a random question, have you added any kind of salt to the tank? Used any kind of air fresheners recently in the room where the fish are kept?

 

[Minstrel]

Just a random question, have you added any kind of salt to the tank? Used any kind of air fresheners recently in the room where the fish are kept?

No the only thing I do with regards to room freshner is candles and they haven't been burnt for about 3 months now. No kind of salt has been added either. I am flummoxed I really thought I was taking good care of my fish and it hurts that I have effectively killed them somehow

 

[laurac94]

Under 0.5 is a starting point but won't be good for even the next few days, but your bacteria should be able to process 0.5 over night easily if it is still alive. You will need to do another large water change tomorrow to get it to 0 and most likely smaller water changes for the next few days until it begins to stabilise. Do daily tests until the ammonia is a stable 0, doing water changes when necessary.

 

[stanleo]

you mentioned that you are away sometimes. How long are you away and when was the last time? Do you leave automatic feeders for the fish?  Who takes care of the fish when you are gone and is it at all possible that during this time the power went out?
 
I wouldn't beat yourself up too much. From all my reading I have found that disasters can happen to the best. I am an amateur and keep expecting this kind of thing to happen to me. That's why I pay attention to these posts.