How often do black tetras outlive their lifespan?

My fish are pretty old, probably ~4-5 years or more. I have 2 corys and 2 black tetras (+ snails) left in a 110 gallon tank, tankmates passed away one by one (for the past ~decade it was corys and black tetras only). I want to "close" my tank in 3 years because I'm moving abroad - worst case scenario, if someone outlives the deadline my dad will take care of them but that's only temporary.

I'm really worried they're suffering without full school, they seem healthy and eating but I don't know...
Currently I have an opportunity to adopt 3 black tetras that are around 2 years old and I don't know if it's a good idea. I had tetras live to around 7 years and of course those are younger than mine and might outlive them (so I'll face the same problem with them). I would really prefer to avoid rehoming, I tried finding them new home previously and I couldn't find anyone that seemed nice enough. Frankly, I'm scared they'll be mistreated in their new home or rehomed again god knows where... (although I'm thinking about trying again because I genuinely want them to live their best lives)

So, I'm curious how long do y'alls tetras live and what would you do in my situation?

(we're not in the US, dumping them in a pet shop is out of question and I don't have anyone who could take them in long term)

 

There is no such thing as a "black tetra".
There are blackskirt tetras (Gymnocorymbus ternetzi), black neon tetras (Hyphessobrycon herbertaxlrodi) and some black domestic forms of other species.
While their live expectancy in the wild is between 1-3 years, with good care they can reach between 4 and 8 years in captivity.
Due to bad holding conditions most don't survive the first year in a hobbyist tank.
You should probably post a picture so we can help ID the fish.

Do you have any kind of private exchange websites like ebay classifieds or the like? Otherwise care to tell us your country? This forum is international, not just US.

 

There is no such thing as a "black tetra".
There are blackskirt tetras (Gymnocorymbus ternetzi), black neon tetras (Hyphessobrycon herbertaxlrodi) and some black domestic forms of other species.

They're black skirt tetras for sure, sorry

Do you have any kind of private exchange websites like ebay classifieds or the like? Otherwise care to tell us your country? This forum is international, not just US.

We do and I tried it once already. I found people with nice tanks, similar in size to mine but their attitude towards re homing is cavalier to say the least... I'm worried about things like them being attracted by other fish (because they're old), or getting sick (and new owner flushing them in the toilet or whatever), or getting re homed again (because everyone seems to be doing that) etc.

We're in eastern europe, Poland to be specific, but I already checked zoos and aquariums. Tbh I'd be willing to pay for someone to just keep them safe and maybe send me an update once a year (if they make it that far) but it doesn't seem doable

 

They're black skirt tetras for sure, sorry

Blackskirts can reach 8 years in my experience. But they have to be in really good care. Usually the magic line is 5.

I'm worried about things like them being attracted by other fish (because they're old), or getting sick (and new owner flushing them in the toilet or whatever), or getting re homed again (because everyone seems to be doing that) etc.

Understandable but when you surrender a fish for rehoming you will have to take this into account. I wouldn't give a fish to someone who would flush it, but all the other things... you have to live with it or otherwise keep them until their demise.
The other things though... No, old fish will not be attacked, at least not by conspecifics and many other fish simply ignore other species. If the fish get sick, it's due to the one who takes them in, as if they made it for quite some time in your care they're healthy. But the chances of them being rehomed again is always there. So once you give them away don't expect updates.

I am very positive you have aquarium hobbyist clubs in Poland, as an acquaintance of mine gets fish and plants regularly from one in Warszawa, so I would look into that.

Ultimately it's your choice, but if you really can't care for them anymore in three years, what else can you do besides rehoming? It is a common and necessary practice in the hobby everywhere and maybe it helps to look at it from the other side:
It gives your fish the chance to live out their lives in peace in good care.
If you don't rehome them when the pressure from the deadline is closing in this chance is taken away. Because then you might settle for just anyone in desperation.

 

Thank you so much for such a detailed reply!

There isn't any time pressure regarding my current fish. They have a home here until they die, even when I move out - my dad will feed them and do all the daily stuff and I'd probably hire someone to do water changes and I'll visit every few weeks etc.

My only concern is that they're schooling fish and they might be lonely, they have everything else to be happy & healthy

Blackskirts can reach 8 years in my experience.

Yeah, few of mine made it to 6-7 too which is why I'm reluctant to take those 2 year olds in
I guess I'll keep looking for older fish and keep mine with me unless there's a really good home lined up

 

There isn't any time pressure regarding my current fish. They have a home here until they die, even when I move out - my dad will feed them and do all the daily stuff and I'd probably hire someone to do water changes and I'll visit every few weeks etc.

My only concern is that they're schooling fish and they might be lonely, they have everything else to be happy & healthy

I think my non-reply to that problem tells it all. It is completely fine to let a group of fish "die out" in a tank if rehoming is not an option. Your tank is big enough.

Just another thing... same (group size requirements) applies to Corydoras as well. And they can (depending on the species) reach 20 years easily.

 

I think my non-reply to that problem tells it all. It is completely fine to let a group of fish "die out" in a tank if rehoming is not an option. Your tank is big enough.

Just another thing... same (group size requirements) applies to Corydoras as well. And they can (depending on the species) reach 20 years easily.

I know Corys worry me too, probably even more because of their lifespan. I wish I knew their actual age instead of just guessing tho :'(

I was mostly resolved to letting them live out their years here but I'll probably try to look for another home, maybe a miracle will happen and someone decent will take them in