fish age and resilience

[yraveh]

Good morning,

is there any evidence that younger /juvenile fish are less resilient (hardy) than older ones?
Money and aesthetic aside- what would you recommend to a newly cycled aquarium?

[AboutAcans]

Ones you don't wanna chase around later to get out.

[A sea K]

In some cases I would say yes but it would be dependant on what fish. Younger/juvi fish will typically have a higher metabolism and will require more frequent feeding than their adult counterpart to sustain them.
There are multiple choices for a new set-up, just stay with some of the hardier species. Look at LA choices for beginner fish as most of them are quite hardy and there is plenty of ideas to choose from.

[2smokes]

Allready Grown fish are hardyer but depends on the fish.You can buy somme mature fish that have a short lifespan of only 2-3 years(like firefish).They look great when you buy them but they are old and die after a few months from old age in your aquarium.

[Timfish]

Generally juviniles are going to be more resiliant as they have not developed reinforced preferences yet. Older fish that have established territories and a set of learned behaviors in the wild will not adapt as readily to captivity and are generally more prone to developing repetitive or steriotypy behaviors or become aggressive towards tank mates. Please note I said "generally" individual personalities trump any reputation a species may have regarding behavior or any characteristics applied just to juveniles or mature specimens. Also note the vast majority, if not all, of the fish we get are going to be juveniles or subadults and as they become sexually mature changes in behavior should not come as a surprise.

[yraveh]

very well. thank you all.