WHAT HAPPENED ? ? ? WHY ? ? ?

[TW]

Hadn't been around the tank earlier in the day & when the lights went on, every single fish was either down & laying on it's side, or mouth down at the gravel, tail up. No one was swimming.

Pics of only some of the sick fish
Wild Royal Blue & Wild Heckel
http://i95.photobucket.com/albums/l128/TankWatcher/138G_523L_Discus%20Tank/081011_sick_000_0668.jpg

Alenquer
http://i95.photobucket.com/albums/l128/TankWatcher/138G_523L_Discus%20Tank/081011_sick_000_0670.jpg


another wild heckel
http://i95.photobucket.com/albums/l128/TankWatcher/138G_523L_Discus%20Tank/081011_sick_000_0666.jpg



Tank History & current test results
138G or 523 Litres
Cycled since 01.08.08.
Owned all the fish much longer than that.
Planted, pressurised C02,
Ammonia 0, Nitrite 0, Nitrate 10-20ppm
Last water change = Wednesday night
Water changes are twice a week @ 30-50%
Water is aged & heated

Last night all seemed normal. Lately, been thinking I might be underfeeding, so after they ate the first lot, I threw in a couple extra pieces of home made beef heart then went to bed.

Anything different to usual
Extra beef heart last night
Saw left over bits of beef heart in the tank today (normally no left overs).
C02 hose had come apart from the regulator. So no C02 was pumping into the tank (instead was pumping into my cupboard).

Action Taken
50% water change
double dose of prime
dose of amtrite down

Slowly they all became upright again. The wilds were the slowest to recover, the heckels (the youngest) were the very last to start swimming again. Neons, sterbais, otos & at least 3 out of 4 apistos are fine. The other apisto might be too, as there are lots of places for a small fish to hide in a 7ft planted tank. I cannot see any dead fish.

They're all looking & acting now as if nothing ever happened. They are scavenging tank bottom, looking for food.

Don't they know what a scare they gave their mum :shock:

Recovered WRB
http://i95.photobucket.com/albums/l128/TankWatcher/138G_523L_Discus%20Tank/081011_recovered_000_0672.jpg

Recovered Albino
http://i95.photobucket.com/albums/l128/TankWatcher/138G_523L_Discus%20Tank/081011_recovered_000_0673.jpg

I'm glad they have recovered, but I don't know why this happened. Maybe I never will, but wondered if anyone can think of anything. The C02 comes to mind, but they have lived through a C02 bottle running out other times in the past, so I wouldn't think that's it.

Any thoughts on the mystery would help. I hope to never go through such as scare as this again. I really thought I was going to be left with all my fish in this tank dead. I'm so glad it happened on a Saturday, when I at least caught the problem just after lunch.

Any clues :?:

[DIY]

Weird for sure.. perhaps the co2 being pumped into the cupboard displaced oxygen around the tank somehow.. would have lowered the O2 levels in the water... Lights off in planted tank means the plants were also using up O2 and the waterchange added some much needed oxygenated water? :ug

[taksan]

Co2 killed the O2 it somehow got into the tank.

Happend to Merrilyn too
She lost a few grand of fish

Co2 should be used for planted tanks but not for tanks with expensive irreplaceable fish

[TW]

thanks DIY & taksan for quick replies
Co2 killed the O2 What I don't understand, though, is if the C02 killed the O2, why it happened when Co2 wasn't even being pumped into the tank :?:



it somehow got into the tank. do you mean that the C02 escaping into my cupboard, made it's way into the tank?


it happened to Merrilyn too ...She lost a few grand of fish Poor Merrilyn. That's so sad. Guess I am very lucky.

[DIY]

It's only a thought..

The co2 concentration in the air immediately around the tank rose to dangerous levels.. the O2 in the water relies on the exchange at the water surface with the O2 in the air.. if the air around the tank had high levels of co2, and the co2 had "displaced" the O2 in the air immediately around the tank then the exchange at the water surface would have been low in O2... and high in co2. That coupled with plants at night using up O2 as well as fish... resulted in dangerously low O2 levels in the water.

The difference is when the co2 escaped into the cupboard it was uncontrolled - and normally O2 is being exchanged at the water surface at the same time - so normally there is fresh O2 going into the water as well as the co2.

[TW]

That makes a lot of sense DIY. I will put 2 clamp ties on the tubing, so this won't happen again. Thanks for helping me understand what happened.

[ivo]

OMG i just saw your post and it is scary, but lucky they all came back ok. imagine you were not home to rescue them? the whole CO2 set up sounds dangerous i have heard a few casualties because of that from various fish keepers. it is like your discus did a bad joke on you or something but very glad for you that they are all ok.

[TW]

Thanks ivo, yes it seems now like it's 1st April & the discus say "April Fool, Mum" or something like that. They are all acting now as if nothing was ever wrong & they haven't a worry in the world.

I was very scared earlier on today, but feel so much better now I have a logical explanation, one that I can understand. I've had C02 longer than I've had discus & this is my first issue with it.

[atti]

Hi TW,

I am glad you did not lose your fish.

Do you have an air pump that comes on at night? Is it in your cupboard?

Also, which apistos do you have in the tank? Just curious.

Cheers Atti

[ivo]

i think any fish keeper will get a fright when they see their fish standing like a cardboard in the tank like yours. its amazing how quickly they can turn around and look perfectly fine in second lots of pictures. anyway, at least you will go to bed tonight as a happy mum instead!

[TW]

Hi Atti

No, I wasn't using any air pump at all. I am going to change that now. Will get myself a timer & air pump to switch on when the lights are off. The pump will sit the cupboard.

I have apistogramma macmasteri (from Thomas, here on the forum) and a pair of german bred Apistogramma cacatuoides. I still haven't seen one of the macmasteri. Not apistos I know, but also have one krib, the last one out of a batch born in my tank nearly 3 years ago. In another tank, I have a pair of Pelvicachromis taeniatus nigerian red.

Yes ivo, I go to bed a happy mum, knowing they're not standing like cardboard.

[Xtreme]

Was it just an overfeed and they had too much in their tummies?
As they came back overnite?

[waitaki]

wow - what a happy ending to a nightmaress story!
Good save TW

[TW]

Thanks Wayne & waitaki for the comments.
Was it just an overfeed and they had too much in their tummies? As they came back overnite? Never be sure 100% I guess, but I'm thinking it was likely to be the C02 / 02 exchange issue discussed above. They recovered quicker than overnight. Can't exactly say the time, as it seemed to drag on while I was watching them, but the 1st fish started swimming maybe 15mins after the water change. Red melon was the first back up & about, WRB 3rd last & 2 wild heckels were the very last.

I did over feed them the night before & for the 1st time, there was uneaten food left in the tank overnight, but the water parameters were all fine.

So I'm leaning towards the C02 / 02 exchange being the culprit.

Wayne, what size air pump would I need for a 500 odd litre tank? Don't want it to be bubble mania in there, but would like some oxygen going in when the lights are off.

Cheers, Robyn

[OZFISH]

This may seem a bit silly, But ive seen some of my discus in the 7 x 2 x 2.5 tank do this when ive first turned the lights on if i had to turn them on late at night for some reason(which is very rare). They seem to go into shock and and just lay at the bottom like they are hiding or petrified. However, this does sound more like a lack of oxygen. Hmmm, any chance the power was off duiring the night and the tank was not getting filltered?

[TW]

Hi OZFISH, thanks for the ideas.
This may seem a bit silly, But ive seen some of my discus in the 7 x 2 x 2.5 tank do this when ive first turned the lights on if i had to turn them on late at night for some reason(which is very rare). They seem to go into shock and and just lay at the bottom like they are hiding or petrified. I know what you mean, but I don't think that was it. Though they started to revive prob 15 mins after water change completely finish, they remained in their almost dead state for too long after the light turned on. They remained like this while I did my water tests & got everything together to begin the water change, as well as during the emptying & filling stages. Half emptying & filling a 7ft tank also takes a little while - still not one was able to make a move. They weren't hiding - they were on the substrate just wherever they happened to be when they collapsed. Many out in the open. A couple were head standing. All the fish too, not just discus.
any chance the power was off duiring the night and the tank was not getting filltered? Power was on, filter was running. I leave my filters running when I water change. The albino discus collapsed halfway towards the top of the tank & landed on a couple of horizontal branches of driftwood. They supported him & there he lay on his side, just barely a little under the surface of the water at the halfway empty mark during the water change. Didn't notice him at first, but he was right under where a semi strong flow from filter return was splashing directly on him. He just lay there coping this water coming down on him. If just a fright, that would have scared him even more & sent him to a safer hiding spot, I'd think.

Thanks for thinking of suggestions though. I really appreciate people trying to help me understand what happened.

[shewey]

Hi TW,

How many BPS did you have your CO2 reg set to output from your cylinder? I would imagine it would only be a couple bubbles every second? This being the case the theory of a buildup of CO2 over the top of your tank seems pretty crazy to me...unless your reg came detached from the cylinder and was free-flowing CO2 into the room. Even then unless your tank was in a tiny room with a closed door I can not see this happening.

What was the kh in your tank? I think your problem was more likely a large ph swing due to an extreemly low (unbuffered) kh. As soon as the CO2 stopped injecting into the tank your ph make have jumped a couple of points.

Good to hear your fish are all back to normal. I have had problems with CO2 line connections coming off as well, so have got cable ties on all mine as well.

Cheers,
Mark

[TW]

Hi shewey
How many BPS did you have your CO2 2-3bps, though I find I regularly have to adjust the screw thing to keep rate constant.


As soon as the CO2 stopped injecting into the tank your ph make have jumped a couple of points. That's just the thing, I expected my pH to rise without C02. pH always rises when my C02 bottle empties & these same fish have breezed through the slow pH rise that occurs each time, though I know it's not ideal.

But pH dropped in this case. I have a pH probe in the tank, which controls C02 to a target pH. The reading on the pH monitor was below the target pH. Forgot to mention this in my list of circumstances (should have). The lower than targeted pH reading seemed odd, as the opposite was what I expected to see. It was a bit of an anomaly, which made sense to me, once taskan & DIY suggested the C02 killing 02 theory. Before that, I'd wondered why the heck pH had dropped, instead of rising. It may have had a long time to slowly reach this C02 build up, as I don't know when the line detached. I didn't check it at all on Friday, but did on Thursday (constantly checking it now).
I have had problems with CO2 line connections coming off as well, so have got cable ties on all mine as well.
I have 3 holding the line in place now.

:ug guess I'll never know for sure :ug but in my very unexpert mind, the theory made sense. Really appreciate your thoughts though, 'cause I'd like to make sure I cover all bases & if you still think it's something else, I'd like to hear. Lot of discus in a 7ft - I'd be heartbroken if they all died.

Might be the wrong place to ask this, but I've been thinking about the air stone I'll be adding & how air pumps work. Might sound stupid, but I don't know how they work. Do air pumps draw air from around them & send that air into the tank. If that's how it works, no point putting the air pump in the fish cupboard. If need be, I'd get a longer air line & place the pump as far away from the tank as I can, maybe in the next room.

Anyone know how this works?

[waitaki]

My understanding with air pumps is they increase the surface area when they break the water surface the ripples create extra oxygen area - something like that. That is why surface area is more important when stocking fish that volumn of water.
I'm sure someone will explain this in more technical terms.

[atti]

Hi TW,

I agree with shewey about the CO2 flooding the top of the tank being a little crazy. The amount of CO2 you are bubbling into the tank is a very small quantity. CO2 is heavier than air and therefore tends to lie in the bottom of the cupboard. You would have to put a great deal of CO2 into the room before it flooded the room up to the top of the tank (I work in a Power Station and we use CO2 as an inerting gas).

Also, that is why I asked you in a previous post if your air pump is in the cabinet. I wondered if your pump was pumping CO2 into the tank from your cabinet. The air pump pumps air into the tank from the atmosphere around it. I think that you will find that you would need a very powerful air pump, in order to have it in another room! Just have the air pump higher than the cabinet.

Cheers atti

[carnival]

glad to hear that your fish have all recovered, it would be a shock to find them like that.
I've been thinking of adding Co2 to my tank...having second thoughts after reading of your experience. Maybe I'll try it on a tank with plants only to start with........