So, the smaller the fish, typically the shorter the life???

[Magnum Man]

I’ve always been a big fish guy… but since I got back into tanks a couple years ago, I’ve got a couple tanks that have small fish… in my past fish life, probably the bigger fish were more tolerant of the Minnesota hard water… but since getting back into the hobby, I realized I needed an RO filter dedicated to my tanks… and it’s not all small fish, as my smaller Hillstream’s seem to last just as long, but my smaller South American Tetras seem to be a revolving door… schools slowly diminish, and seem to need replenished, while the next size up, several are now a couple years old… just seems to be the smallest of the South American tetras… the schools are there, they just slowly seem to be missing members, until I add a new group to the shoal…

Are they naturally shorter lived, or am I missing something about their care / diet???

BTW... I’ve not lost a Pristella in 2 years, yet the Rummy’s and smaller tetras seem to need replenished more often???

 

[Back in the fold]

Many fish seem to go about four years . Some big cichlids up to ten but most fish seem to fizzle out at two to three . Betta’s don’t seem to be living as long as they used to . That’s what I see anyway .

 

[TwoTankAmin]

I have only kept 3 loach species. The first were yoyos and when they started to harass my DD black angels, the loaches went out. Next came my real love, clowns. I have had some for over 20 yers now and the biggest twoa are between 10 and 12 inches, But not long after I started to accumulate the clowns I was turned onto sidthimunkis aka dwarf chain loach. I started to assemble a group and I still have most of them today which is also about 20 years. So, much for smaller fish being short lived.

And if you want to consider zebra plecos a small fish, then I have had some go out to new homes at the age of 20+ years (the zebras not the homes).

And then there is this. I am about yo turn 77 in a few months. At my peak I was 5'5" tall. Today, thanks to gravtiy and time, I am barely over 5'3". So much for smaller people not living long. My 5" tall mother passed at age 96. Somebody needs to tell Randy Newman that short people have plenty of reason for living long. We only do it to prove him wrong.. Small fish are the same.......

 

[MaloK]

My most difficult fishes are tetras, I never had them breed in my water and they rarely lived longer than 3-4 years at best. One friend in a nearby city could make them multiply without effort and they lived 6-7 years not knowing exactly why.

They seems to be more delicate and require specific water parameters to thrive. Also crowding and mates induced stress is a good long term factor too. Larger tank mates always have an impact even if not a direct threat.

 

[emeraldking]

I don't think that bigger fish will automatically outlive smaller fish. Size itself isn't a factor to determine the lifespan of a fish. Even I have smaller fish older than books tend to claim. Other factors will be in play to influence the lifespan of a fish.

 

[CassCats]

My cherry barbs are currently 7 years old and still kicking. I just lost my oldest skirt tetra, he was also 7. Still many others still up there in age.


Some small fish can live a long time. Pangio loaches are reported to make it 20-30 years, and oldest corydoras was one kept by Ian Fuller made it to 40 years old.

Some things, it's genetics that'll play a part, but good care, temperatures, parameters, diet, and a bit of luck to get them thriving. Fish kept at the top range of their temperatures won't live as long of a life either.