Very Confused

[Vimmer]

Ok I'm at a loss. Did weekly WC on Saturday. Before change parameters were ph 7.8 as usual, ammonia zero, nitrites zero, nitrates crept up to 60.

Yesterday every thing seemed fine. Dosed liquid co2 this morning same as every day. Came home tonight to a floating pristella tetra and a glow light with faded colouring and very inactive. Tested and everything in normal range. Ammonia zero, nitrite zero, nitrates 20 ppm. Invertebrates in tank (2 mystery snails and a bunch of ghost shrimp) are all fine. No signs of illness on carcass just dead.

Any ideas what might be going on? Could it be using liquid co2 instead of gas/ poor fish in wrong place at wrong time when dosing?

[Jayba]

What is liquid CO2. Excel? Nitrates at 60 is way too high for my comfort level. Kinda need more details

[ckmullin]

A fish swimming through the liquid co2 dose could easily be killed. I always suggest it to be diluted before hand or to be dosed right at the filter output so it's diluted quickly.

Sorry to hear the loss.

[Vimmer]

Always dilute 60% h2o 40% liquid co2, (API CO2 booster). And always inject into tank right at Return nozzle (fluval 305 canister). First fish loss since setting up in late august. Lost pretty much whole first purchase of ghost shrimp but was still getting ammonia and nitrate spikes then. Lost a mystery snail back then too but other two are doing great. One seems to have grown faster than his shell and doesn't pull all the in when he sleeps, tucks up and hides antennae and organs but his foot sticks out 1/8-1/4".

Oh and second fish that had lost colour was lamp eye tetra not glow light. Back portion of body that's usually black was grey. All other tank inhabitants

Tank1 36G bow

Inhabitants: 6 neons, 2 ottocinlus, 4 fire and ice, 4 candy cane, 4 bloodfin, 3 pristella, 4 orange Von rio, 5 glow light tetras, 4 lamp eye tetras, 2 mystery snails, 10+/- Ghost shrimp

Plants: red ludwigia, cabomba Carolinas, wysteria, scarlet temple, sword???, crypt. Becketti, banana plant, small portion of Christmas moss.

Seem to be fine and good colouring. Know it is full bio-load and at this age tank is still maturing. Just seems odd that after three weeks of fairly stable number it was two medium sized fish were affected and not the small ones. I've always used the neons as my canary. If they start losing colour there's usually a problem in the tank.

[geleen]

Two things to consider, the size of water change, if nitrates went from 60 to 20 that would indicate a 60-75% change.

If your fish are not use to that stress could result in death.

And perhaps not enough water conditioner.

Edited December 2, 2014 by geleen

[Psylant]

To further what geleen said... Too much/little water conditioner? Too hot/cold of "fresh" water? Possible that your substrate is too deep/undisturbed and released some nasty gasses? These are scenarios I can think of that are not disease related and would "test" fine.

[Vimmer]

Leaning towards fish in wrong place at time of co2 dosing. It was a 30-40% WC; not the largest since setup but bigger than normal. Temp may not have been perfect but was within 2 degrees F. I've been gravel vacuuming top 1-1 1/2" weekly so doubt gas build up given tanks is still young having only set up in late august. The pristella that died was one of earlier inhabitants the lampeye that had lost colour was one of last added approximately a month ago.

What's really making me think it was co2 is that inverts were all fine and the lampeye seems to have recovered tonight and back to normal colouring. Anyway will be keeping close eye on things this week.