life span of predatory characins

[RampageRR]

Piranha live for 20+ years as well in the wild. If there are characins with short lifespans, it definitely doesn't apply to ALL characins. Some live for extremely long times.

Case in point, do you really think a goliath ATF is capable of growing 4+ feet long and 80+ lbs in less than 4 years?

 

[JD7.62]

I wouldn say the above is a valid argument. There are several fish that can grow that big/fast in four years.

Mahi-mahi for example live only 4-6 years and can get 80+ pounds in that time, though rare.

 

[Chicxulub]

I wouldn say the above is a valid argument. There are several fish that can grow that big/fast in four years.

Mahi-mahi for example live only 4-6 years and can get 80+ pounds in that time, though rare.

Dolphins also live in a much richer environment. While they're comparable in size to an adult GATF, they don't fill anything approaching the same niche as one. Comparing a dolphin fish to a GATF is an apples to tennis shoes comparison; the dolphin fills a mesopredatory trophic level comparable to a riverine cichlid that the GATF might encounter and the GATF fills the same niche as a mako shark or marlin that the dolphin would encounter.

It stands to reason that an that an animal who is an apex predator who lives in an environment that can only support a 4' apex predator would take much longer to get to its maximum size than a forage fish who lives in a much, much richer environment. The fact that we're comparing a mesopredator to an apex predator is indicative of the problem with this argument.