Slow die off has consumed nearly 20 fish!

I was losing about 1 fish a week and couldn't seem to nail down the culprit. I haven't lost a fish in nearly a month but today one of the tetras are showing symptoms again.

I'll try to list all the info asked for in the diagnostic sticky.

40G Breeder setup with plants on 8/7 and fish added with a mature XP3 on 10/30.
~30 ember tetras (lost about 10 now all but 6 were purchased at the same time as the cories at the end of Sept and were QT for 4 weeks)
~5 panda cories (lost about 7 now)
~5 Otos (bought around same time as amanos a year ago, none lost until this)
~15 Amano shrimp (none lost)

CO2 Injected
No ferts recently
50% WC weekly

Just tested with API
pH - ~7.0
kh - 11
gh - 9
Ammonia - 0
Nitrite - 0
Nitrates - 10

Ember tetras exhibit....
Swollen belly (scales at the lowest section of belly are slightly protruded)
Loss of appetite
Gasping at surface
Slight cloudiness to skin, lost it's sparkle the ember tetras have
What looks like internal bleeding, a red dot here and some red squiggles there, not constant or consistant.

Some of them had dark blotches under skin in QT (4 weeks) but showed no other signs of illness and did not die. They have all since developed mentioned symptoms and passes away. The fish that is currently sick is the first to not have the blotches AND is one of my orginal 6.


Panda cories exhibited....
Paleness in their lighter sections (black stayed black while the off white/tanish parts went white)


The cycle I have seen with the ember tetras (cories die within a couple days with no signs of illness for a good 5-6 days in between)

Day one - no signs of illness
Day two - 1 fish might not be schooling as well
Day three - fish hangs out at surface
Day four - swollen belly, gasping, red spots, cloudiness
Day five - same
Day six - dead
Day seven - no signs of illness
Day eight same as day one

When the ember tetras and cories die they go limp get pushed around, try to swim very unsuccessfully (upside down, sidways etc.) go limp again etc.

From my research it could be parasites, bacterial or require anti-botics. The symptoms fall in many categories so I don't know how to treat it, where is the safest place to start? Sorry it is so long but I'm tired of watching my fish die, especially when I treat them so well!

Thanks for the replies. That is a very long article! I am still reading it but it sounds logical so far. I was considering buying a canister filter with built in UV lamp so I will get moving on that, and that covers A LOT of bases.

Still open to suggestions and ideas.

I can get an updated overall picture in a little while but I have tried and tried to get close-up pictures but they don't come out worth anything. I WISH I could an up close picture, I've been tempted to ask someone to come take a picture for me!

Best I could do. I just did a WC before lights out so the water is bubbly, making it look cloudy. The flash washes out the detail some but without it the under side of the fish is too dark. Pardon my tanks messiness.

It's eyes are slightly bulgy and I noticed a white spot on it's right side, kinda looks like the scale is lifted. I have never seen that on any other fish though.

Please click the photos for a MUCH larger view.

I got 13 pandas & 31 ember tetras around 9/20. They went into QT. I lost 4 embers and 1 panda within the first 2 weeks but none after. On 10/30 I added them to my 40 breeder and within a week I started losing 1-2 a week up until 2 weeks ago (over estimated the month, just felt like longer with the relief).

CO2 is pressurized since day 1 and diffused with an inline reactor on the output of my XP3. It is all on timers & I always keep slight surface agitation. Actually a little over a week ago my CO2 tank dumped & I found 2 cories and an oto lying on the substrate but I grabbed them & put them into a floating box, increased surface agitation and they all bounced back. I have not refilled my co2 since then so they have been without co2. I just looked at my original post and an entire line is missing in the test results it should have said current pH - 8.1, ph with co2 ~7.0 (I actually typed up the core of that post after the last death a couple weeks ago but decided to keep trying to fix it myself, when I saw another one with symptoms I decided it was time to get help)

The netted things are moss over rocks and were added a couple weeks ago. I used the same netting for the large fissiden fontanus patch in the back of the FTS, I have had it in a couple tanks and for a long time so I know the netting is safe.

I am setting up a QT tank again right now for sick one. I have QT other sicks ones, kept strict WC schedule, removed possibly dead/rotting lilly bulbs, cleaned the filter, added salt and kept lots of surface movement with the filter output and an airstone.

I should also mention I do have Mineralized top soil in this tank under black sand flourite. I have had bubbles coming out of it but I poke the substrate to release the bubbles right before WCs & was told it shouldn't hurt the fish.