Dead Discus & all my Rummynose & Tetras!

[Del]

We woke up this morning and found one of our 2 discus dead, 6 rumynose dead, 2 silver sharks dead & 8 cardinals dead!

My remaining discus is quite pale with black bars, not swimming very well and just hanging at the surface now... so are my remaining dwarf gourami and 2 silver sharks...

I have a 3ft planted tank, running an Eheim and I use aged water for changes with ferreal every time and florena once a week. My stats this morning were...

PH 7.6 (it has always been about 7-7.2)
Nitrate 40mg
Nitrite 0
Ammonia 0
Temperature 30

I did a water change day before yesterday (I do 30% every 2 days) and the only thing a did differently was a really deep gravel clean and did not have the spray bar splashing the water at the surface as much as I have done in the past. I do not use an airstone as I have quite a few plants.

I have read up on this but can't find much else to do except what I have now done...30% WATER CHANGE, ADD AN AIRSTONE, PUT THE LIGHTS OFF... CRY...

Any other suggestions... SHOULD I DOUBLE DOSE GEO LIQUID OR ADD EPSOM SALTS OR BOTH...?

Was it the really deep gravel clean that caused this? Did I take all the good bacteria out? Or was it the lack of oxygen? I just feel awful....!!!! :( :(

[Merrilyn]

Oh Del, that's just awful. I'm so sorry.

I do feel it was the lack of oxygen that caused the problem. That's a fairly heavy bio-load in a three foot tank, and at night the plants take up oxygen too. (They only give off oxygen in daylight).

Moving the spraybar probably caused the problem, allowing less oxygen exchange at the surface of the water.

Adding the airstone was the right thing to do. Don't add anything else, certainly not epsom salts. Just let your remaining fish recover in clean water.

That nitrate is a bit high, do another water change to bring the reading down.

And don't be too hard on yourself. We all make mistakes.

[Del]

Thanks Ladyred. My other discus is now hardly breathing, just lying at the bottom. The gourami is hanging in there and another silver shark lost the battle. I've ordered another 2 discus from Rod Lewis and he is getting them to me on Wednesday, ironically to keep these company - should I just forget the whole thing? I just don't want to keep making these mistakes with these beautiful fish!

[Merrilyn]

That's tough Del. I know it makes you feel like giving up.

If I were to tell you how many fish I have managed to kill in my 30 years of keeping fish, you would be shocked.

We all make mistakes. Fishkeeping is a learning experience, and we move on, learning by our mistakes.

Don't toss things in just yet. This next pair you get could live to a ripe old age of 12 or more.

[Del]

Usually I clean the gravel at the surface - about 1/3 deep - I was thinking maybe it just wasn't cleaned throughly enough over the 5 months we have had it. We replaced our exsiting 3 year old white gravel about 4 months ago, at the same time as we switched from a hang on filter to an Eheim.

Our current layer of gravel is about 5-6cm deep - so how much do you clean the gravel in a planted tank - completely - to the bottom of the glass floor? So that there is nothing but clear water coming out of the gravel cleaner?

I know it is a basic question, I am just trying to get everyone's feedback as I am hoping all this loss is because of a really simple oversight...? :oops:

[Del]

.. thank you Merrilyn for your support - I feel a whole let better and I really do want to try again...

Rod wants to wait till I have my water checked tomorrow at my LFS and maybe trial some neons for a few weeks before he sends my new discus babies over... smart man!

[Bill T.]

I vacuum my gravel once a week, but always do a thorough job. I push the plastic tube right down to the glass bottom, and work through the whole gravel area systematically, skirting around plants so I don't wreck the root systems.

I have heard that it is possible to get pockets of anearobic bacteria build up, and this can send a blast of very toxic stuff through the tank.

Also, I wonder if something else might have happened during the night, like a power disruption for a couple of hours? This might allow an ammonium build up, plus they could get a chill. When the power comes back on, everything returns to normal, but the damage is done?

[Insomnia]

I didn't see any mention of this and I highly doubt it had anything to do with the sudden tragic loss of your fish, but your ph is too high for those discus. You should always try to keep it below 7 around 6.5 if possible. Just thought I'd give it a mention.

[Trebs]

7.6 is quite okay as long as it's stable.

If you do end up loosing all the fish I would suggest waiting a while before getting anything new. It is a good chance to switch to a bb tank and cycle the tank from scratch then go back to Rod when you are ready.