species die off... mysterious case of the missing Pristella's

[Magnum Man]

so, I have a thriving tetra tank, with now, many species of south American tetras in it... some of my 1st tetras in this tank were rummy noses, and pristella's... today there are many varieties, that have been here for some time... these 1st tetras were added over 2 years ago, and some time ago, I noticed all the pristella's are gone, while there are still several rummy noses.... the pristella's were originally very hardy, when I added them... at least for the 1st years... but now they are completely gone, while other species may slowly lose the numbers in their groups, the pristella's disappeared completely, before I noticed... could they all have been the same age, and died around the same time, of old age??? just seems weird, to lose them all, while everyone else is thriving, and not witnessing any fighting or bullying... has anything like this been noticed by anyone else???

 

[GaryE]

They should be able to live for 7-8 years, and stores generally sell them at 3-4 months. It's an easy to breed tetra, and I've raised them. They reach adult, sales size in record time.

So it can't be age.

They're generally very hardy, as one of the first tetras in the hobby, way back when. The only things I can think of might be a species specific slow moving sickness from the supply chain - maybe Mycobacteriosis, or something you're doing wrong and haven't identified yet. That doesn't help a lot, but when I see similar things, I usually know the fish in the tank aren't thriving and I need to review temperature, water change routine, tankmates, stocking, etc.

My big project of the week is tearing down a large tank where I feel things aren't going right. I don't know why, but I have lost a few tetras in it, and I have an "I can't identify the problem but" feeling that to go on with that set up isn't wise. Motivation wise, it also helps that the tank is uneven on its stand, which has to be tweaked. So 2-3 solid hours of work are needed to get that aquarium back on track, I hope.

Any unexplained or even inexplicable die off is a serious message about something we're doing. It can be hard to pin down.

 

[Magnum Man]

they originally came from a seller I no longer use, but they went through the period before I started on RO, so maybe internal damage from improper water , also that particular seller I think uses the cheapest Asian suppliers, but they did last at least a year here...

 

[Innesfan]

As @GaryE stated, Pristellas are one of the veterans of the hobby and back in the day were recommended to beginners due to their hardiness and the readiness with which they spawn. That said, they have been farmed to the max and the gene pool well-worked--witness the variants now vailable--so the current stock, unless wild caught, is likely not as durable as they once were.