Frustrations with a bazinga!

[Lurch1]

So I have had some fish deaths over the last week that have angered me basically because I am not sure exactly what occured. I have a soil substrate so when I rearrange plantations I am supposed to do a 75% wc after (from what I have read). I lost 2 hatchets, a juvenile pleco and a cory. I ran an firestone on high as soon as I noticed, but it was to late for them. Today my saulosi tank sprung a leak and I had to take it down and sell my fish to BA. I moved my apistos tank to that location and had to remove 80% of the water to move it. Well again I lost 2 neons, a pleco and a cory. Kinda ticked. Any ideas? Does cold well water have much o2 in it? Water parameters are not changing.

What's the bazinga you might ask? BA got some double red agassizi apistos and I got a pair. Super stoked!

[exv152]

what are your parameters for ammonia, nitrites, nitrates etc?

[Lurch1]

They are all good, 0 0 and 10.

[fischkopp]

Does cold well water have much o2 in it?

How cold is the water, or phrased differently, what's the temperature in the tank after the water change?

Do you see A LOT of air bubbles building in the tank after the WC?

[Lurch1]

Tons of bubbles. Temp is around 70 to 75 maybe. Running temp is 79.

[sas]

How old is your tank? 
Any chance there is sulfur dioxide forming in your sand bed?

[fischkopp]

Tons of bubbles. Temp is around 70 to 75 maybe. Running temp is 79.

Temperature sounds ok. But any lower is going to be risky.

Dissolved gas is a big concern though, and can kill fish. Water that is absorbed by the fish will release gas inside the cells, which can lead to complete bursting of the cells. This can be fatal if complete organs are affected.

One way to avoid that is to get rid off as much dissolved air either before the water gets into the aquarium or while the tank is being filled. That's one reason some folks age their water. When filling straight from the tap, make sure the water splashes as much as possible, as this will release most of the gas. That's what I do.

[exv152]

Aging water is important in my experience. I know many people haven't had any issues just filling straight from the tap with some dechlorinator, but I don't take any risks. I age the water for about a week in a 33g drum with some prime and an airstone running 24/7. It's probably overkill, but I've never had a single issue with WCs.

[Lurch1]

I don't have the space to age water unfortunately. The two time it happened there was soil disturbed with a bunch of bubbles. The tank is newer, 3 months or so. I haven't had any issues with try water changes only when things were churned up. We plan on moving next year and a fish room will be in order.