i haz a sad, a big sad :(

[Oblivion]

pwc on my 4ft fry tank on the weekend, all good.
last night done a small clean to get rid of excess food so i could move the clean CC sand to the other half of the tank and leave the other half bare glass bottom to feed down that end.
it stirred things up a little, the fry got a bit scared of all the activity but seemed fine afterwards

today i wake up, all my 8 astatotilapia latifasciata fry are stuck to the filter intake, dead.

not sure what killed them, theyve been going so well right up to feeding time last night, looking very good and healthy, strong appetite, swimming and playing with each other.

nearly 3 mths worth of raising them to this point, and now theyre all dead.

im so bitterly frustrated with myself

 

[Oblivion]

1 survivor, as fit as always.

7 dead. eyes bulging out a fair bit, lips pouted.

they measured a shade over 2.5cm / 1"

im thinking it was when i moved the CC sand, pushing it to one end of the tank, which happened to be the end nearly all fish were hiding at.
i know one fish definately hid near the filter, which was the end i was clearing.

could it be they somehow choked on sand that was kicked up ?

pisces natural products, micro crushed coral sand

 

[slitherbomb]

How long has the tank been setup? Over time, toxic gas pockets get formed in the substrate, so they could've been released when you stirred up your substrate.

 

[shadowstars123]

How long has the tank been setup? Over time, toxic gas pockets get formed in the substrate, so they could've been released when you stirred up your substrate.

Seconded to this

 

[HUKIT]

How long has the tank been setup? Over time, toxic gas pockets get formed in the substrate, so they could've been released when you stirred up your substrate.

I don't have a explanation but the gas pocket killing fish myth is right up there with Santa Claus and the Easter Bunny. Sorry about the fish.

 

[jetajockey]

I agree Hukit. Potting soil tanks often form gas pockets causing the tank to burp regularly in the first couple months of setup. I think it would take a crazy massive gas bubble to mess up the water so much that all the fish would die.

I'd lean more towards your water change procedure, did you temp match the incoming water? I see you are using CC, is the tap a huge ph/hardness jump from whats in the tank? Fry can be very sensitive to change.

 

[Oblivion]

i set the tank up about 10 days ago using substrate, filters, heater, airline, ornaments, from my existing 2ft tank.

the fry were in it for about 7 days, levels have been fine on w/e when i did 25% wc, it gets little vacuum's every 2nd day with just a wide hose off my siphon, picks up the excess fry food from the substrate nicely without taking much water.
so water loss last night was so minimal i didnt replace any. (it was just an after feed mini clean)

last night i decided to move the ccsand down one end, so i can feed directly above glass bottom, making cleaning it all out a little easier.
they decided to rush down that end and i think they copped the wash as it was stirred


i think i was a bit rough with moving the sand, while my other cichlids never mind in the main tank i think maybe the fry were more sensetive to the particles which take a while to settle.

i checked levels a minute ago, no amm or ni, or na, due to pwc on weekend.

edit: i had 1x 10kg bag of sand in the 4ft tank (about 1" deep) which is about half what i'd normally use.

 

[HUKIT]

This is a new set up so there's nothing to disturb in the substrate, especially with 8 fry. I killed 9 cherry barbs yesterday after forgetting to turn the filters and heaters on after a water change(first time for that one), there's lot's of possibilities from temp change to huge a huge swing in PH. Luckily moutherbrooders breed very quickly so within 30 days you'll have more.

 

[OsciTheOscar]

is that a malawi? "astatotilapia latifasciata"

 

[HUKIT]

is that a malawi? "astatotilapia latifasciata"

They're from Lake Victoria in Rift Lake Valley.

 

[OsciTheOscar]

thats a nice lookin fish...

 

[WendiDell]

There may be another explanation. A few months back I had 7 Danios in QT and a Common Pleco and two 3 inch Angelfish in a 55g tank. Normally I do PWC on all 4 tanks at the same time,but this day I only did those 2, don't remember why.

Any way, 2 hours later I went to check on them and all the Danios in the QT were dead. One Angelfish was dead and the Pleco and other Angel were badly burned around their eyes.
I won't go through the story of the whole clean up that was needed afterwards. But, it turned out that on that day only the water company had something go wrong with the water. Nothing that would hurt humans but fish died from breathing what ever was in the water that day.
When I do PWC all I use is Prime and tap water, I don't add any chemicals.
I was fortunate that I hadn't changed all four tanks like I normally do. I could have lost every fish I have.
The Angelfish died later on from being bullied by another Angelfish. The Pleco has recovered fully and is now so big that he's going back to the LFS to be rehomed.
Check with your water co. to see if they have had any problems. It may have nothing to do with anything you did.

 

[Oblivion]

thanks for reminding me, i do have a very young albino pleco in there with them, maybe 1 + 1/2" at max.

he still lives, and today my last fry is still kicking on strong.
last night i added a holding female, she's still going well.

no water changes have been done since the w/e, which means no changes since the majority of fry died.

i have noticed our water is becoming much harder, mainly because now any dribbles of water on the outside of my tank become crusty white stains which take a bit of work to remove.

i have been using nothing but prime and tapwater with my tanks for about the past 2-3wks.

id also like to thank all who have replied with suggestions or comments, all advice is always appreciated.