Fish dying from cold or rotten roots?

[sage08]

This weekend i had 2 ottos, 1 cardinal, 2 guppies and 1 betta splenden (White) died. I did a rescaping and uprooted two nuphur japonica (Japanese lily) and one cryptocoryne.... they were not doing well and had been there for some time. The decay roots let out a horrible smell when i remove them. I also added a few plants here and there..

At the same time, the water temperatre dropped from 29 degrees to 25 degress on sunday due to non-stop rain.

Now my other two white bettas ate not behaving like themselves, hiding in the caves and logs. The other fishes seems a little stressed out.

My question is will these two factors cause a change in water parameters, enough to kill the fishes??

[benny]

While you were rescaping, you could have disturbed the substrate and hit pockets of anerobic areas. These dead spots sometimes produces Hydrogen sulphate gas bubbles too. They smell like rotton eggs. The foul smell from dead roots indicated that they were already dead and rotten.

The fishes could be affect by the Hydrogen sulphate gas as well as the other base fertiliser leeching into the water column during the rescaping. Excess metal content and N (Nitrogen) content in the water can kill the fishes.

As for the temperature, there drop was gradual and should not affect the fishes that much.

Cheers,

[|squee|]

Like benny said, definately hydrogen sulphate and probably ammonia as well. Do water changes!

[PeterGwee]

There will be a drastic reduction in O2 levels as well if you don't do the water changes.

Regards
Peter Gwee

[XnSdVd]

I'm in agreement with the gurus. I'll add that methane is also released when plant matter decomposes. Though I have no idea what it does to fish.

[valice]

methane is deadly in sudden huge amounts... that is why some workers can faint and die when servicing in a poorly ventilated sewer manhole... and it would probably be the same to the fishes...

[Justikanz]

Never heard of methane problems (in fish tanks) being mentioned anywhere in literature before leh... Hmm... Got to check on this matter soon...

[XnSdVd]

I learned it in geography... hahaha! for an example, most people know cows produce alot of methane in the form of farts... this comes from all the plants they eat.

The methane is actually a byproduct of the bacteria in the cows gut.

[Justikanz]

Ya, but that's caused by the digestion of vegetable matter. Decomposition also creates methane gas... But in water... Dunno leh... Need to read up to confirm...

[XnSdVd]

sewers are full of methane and water... so it's quite likely.

[sage08]

hello, thks for the responses. I did not change the water, for the sake of science (actually no time lah) and here's the chronology of events:-

Saturday - Rescaping, pulling of roots etc. Some bubbles were emitted with the roots. Probably methane.. Notice that one pleco who "sleeps" at the ammonia alert plastic piece were not present tht night.
Sunday - 2 pleco dead. Bettas not behaving like themselves. 2 black guppys dead.
Monday - 2 bettas dead. No ammonia alert, nitrate and nitrate nil. Fish do not eat.
Tuesday - 1 betta ,1 gurami, 1 SAE dead. Tank begin to stabilise. Fish started to feed again/.
Wednesday - tank begin to stabilise, 1 glowlight tetra dead.
Thursday (today) - Tank stabilised. No fish casualty.

Fauna left:- 9 Cardinal, 5 Neons, 5 rummy, 4 yamatos, 1 SAE, 1 striped loach, 1 gurami, 1 leopard skin cory, 1 transparent loach, 3 guppys and one catfish. Unfortunately, this saga has wiped out my entire collection of White Betta Splenden from JohnC...

The funny thing is all the tetra were unscathed except for the glowlight. Hmm.. i'm actually wondering if it is due to frozen bloodworm kept too long..

[Justikanz]

Gas is Hydrogen Sulphide... Did you try to smell the gas? It should smell like rotten eggs... The gas could have caused part of rhe deaths...

It is near impossible to get nil nitrate readings. You might want to check your test kits for accuracy... The disturbed substrate should have caused some ammonia or nitrite spike and subsequently, the nitrate level should be higher than normal...

[michael lai]

Dear Sage,
If your thermometer is working properly, a drop of 4 degrees is serious business. Enough to kill, I would say but I suspect as what the others say, It is likely due to what you took out from the substrate.

[BFG]

I doubt methane is the cause. But there is another possibility. Phosphate burping. But this happen in marine environment where a deep sand bed is employed. It could be possible but I am just speculating.

[PeterGwee]

Nah, stop imagining things. He refuse to do the water change because he is lazy. Thats about it. O2/NH3 plays the big role in killing stuff since most don't catch it easily.

Regards
Peter Gwee

[BFG]

[sage08]

Thks.. learnt a lot. I did not manage to catch the smell of the gas. But the roots really stink. Wut surprises me is the hardy fishes like bettas, gurami and guppy succumbed but not the tetras.. Even the yamatos are still alive...

Btw, my tank is not small ho, measuring 119cm w, 47 cm d and 71cm h = 400l or 105 gallon.. Can the gas really cause such an impact to the extend of changing water parameter..

[XnSdVd]

Let me put it this way, we've had it happen in 6ft 180 gallon tanks before Like mine, all i did was pull the DW out of the substrate and the next morning all my loaches had ICH.

[sage08]

Let me put it this way, we've had it happen in 6ft 180 gallon tanks before Like mine, all i did was pull the DW out of the substrate and the next morning all my loaches had ICH.

Interesting.. I guess the next time it happens, water change will be made immediately. How much water change do you suggest? 50%??

[valice]

I am so scared of ich now that whenever I do rescaping or moving of the substrate, I dose salt solution after that for a couple of days to make sure that whatever ich spores decide to escape from the substrate dies! Not sure if this is a recommended way though...

For water change after any scaping, large water changes are normally recommended by the folks in here...