pockets anaerobic gas are no myth....unfortunately

gregga

I'm Mighty Megala..(wife: whatever)
Jan 8, 2000
140
0
16
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Long Island
Hey all......
Just wanna post this so maybe no one else will make the same mistake I did. I keep 12 tanks and about 200 fish and have been in the hobby about 8 years.
Anyway, I have a 20G high which about 6 months ago I placed under a 55G on a wrought iron stand. I was using the tank to growout 20 Labidiochromis Mbamba fry. But because of the height of the 20 there wasnt ideal access into the tank. Add that to the fact that placing the tank so low to the ground made gravity less than helpful trying to siphon and do water changes. This is the only one of my tanks that I sometimes need to resort to using a bucket. I normally will clean the gravel/sand in my tanks when I do water changes, however this substrate had become pretty packed down (apparently trapping the gas). Well, last week I moved the tank to a pedestal in the corner of my fish room & did a water change. After only about 10 seconds I saw some large bubbles coming out of the substrate. No more than 30 seconds after that every fish in the tank was dead. 6 months wasted. I'd consider myself an experienced hobbyist who rarely loses fish. I'm sure most of us have heard of anaerobic bacteria. Well, I can vouch for the fact it is real....So if I can help someone else not make the same mistake.........
The good news is that Mbamba female is holding again......
 
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That really sucks. I'm sorry, and I hope things work out better for your fry this time.
 
man, im so so so sorry eh. i would hate that. espicially the fact that they were fry that u had bred :(.
hey, can u please go into more detail on what this gas is, cos im quite intrigued cos i think one of my lfs has it :S
cheers
 
Anaerobic pockets can and do happen in a moderately or heavily planted tank.

It is not the H2S in the pocket that gets you, it is the disturbance that releases it into the water column.
 
It's the natural result of bacteria breaking down nitrates. These bacteria only thrive in low oxygen areas, such as deep substrate that isn't disturbed regularly. Plants help, since their roots wiggle through the substrate, but not enough to prevent pockets. Shallow substrate, UGF, or regular cleaning in the entire substrate, especially under rock/wood will prevent it.

Of course, it isn't bad that it happens, it's just bad when the pockets are distrubed.
 
Is this gas the reason occasional big bubbles come up from my gravel? If the bacteria in the gravel produce this stuff, I guess it is good to see the occasional gravel burp. Another good reason to have slightly larger than fine sand substrate I guess. Thanks for the cautionary tale.

RTR, you say the gs is H2S? In english that is sulfuric acid?? And what did you mean by "It is not the H2S in the pocket that gets you, it is the disturbance that releases it into the water column." ?

What exactly is it that killed the fish?
 
Left undistrubed, additional bacteria will break down the by-products into harmless components. This is the normal process in many lake and pond beds. When it's disturbed, instead of being harmlessly contained in the substrate, it gets spread all over the tank and in the water 'at-large', so to speak.
 
RTR and Onion Girl have it right..........

Hopefully this post will help others.........thanks for all the replies....

Gregg
 
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