mystery death

[GlubGlub]

This is the second time I've had mystery death of a bloodfin and I'm looking for help diagnosing so this doesn't repeat. In both cases I've had an otherwise healthy bloodfin tetra die with no visible symptoms. Great coloration, no visible physical trauma, eyes look good, scales look smooth, but found lying in it's back on the gravel and not responding to any stimulus.

Both happened immediately before a water change. Pretty sure I found the fish immediately after death. I was messing around with plants prepping to remove water. Lots of diatom manual removal, and loosening up unhealthy plant material to suck out. Once I was spot treating with h2o2. The second time I wasn't. A couple months between incidents. Tetras obtained in October.

Water parameters tested normal. (0, 0, 30 and 0, 0, 20 via api master). pH and temp normal. Not the weakest fish in the tank that died - I have a one eyed blood fin named Cyclops with poor coloration who I never see eat.

Something localized released into the water that then dispersed? Could I have physically knocked a fish and caused this? How can I avoid a repeat?

 

[GlubGlub]

Bump, any suggestions?

 

[Delapool]

How similar is tap ph perhaps?

 

[GlubGlub]

Tap pH doesn't vary. It's7.6 or 7.8 depending on how you read the scale, but it's never wavered. Liquid rock.

 

[Delapool]

Bit odd - how often do you water change? It sounds like some sort of chemical shock still.

Is tap temp close to tank temp? Just throwing them out to see if any ring a bell.

 

[GlubGlub]

Once a week, 50%. Temp is within a degree of the tank's. The deaths happened before the water change though. Nothing had gone in the tank except my hands.

 

[Delapool]

Were they all still eating and schooling well?

Maybe they can't quite handle the water if something adds stress? Must admit I'm out of ideas.

 

[GlubGlub]

Yeah, everyone else is doing ok. Could a fish due if it got physically bumped? I don't think I did that, but I was in messing with plants.

 

[Delapool]

Maybe if squashed? I've had them even so often jump out over the years and if they are lucky I've found them in time and put back in with mainly no problems.

 

[GlubGlub]

Hmm, well that makes me feel a little more comfortable, because I'm pretty sure I would have noticed if I bumped a fish harder than it would get bumped falling on the floor.

I guess something must have been released from the substrate or something while fiddling with plants that shocked the fish in a local high concentration. Thanks.

 

[Delapool]

Good luck! Hope all goes well.