Correct but some people are allergic to scalpels... How quickly a body could transition from one material to another is a valuable quandary to wade through and whether the body would adjust to the new reality without issue is another entirely; if aging were not a problem, old men would out-compete young men in any dating pool as they would quickly recover from hormone deficiency and production issues...

Can I put shrimp in the tanks and place the concept on my roof, that I may enjoy sushi on a monthly basis?

Would go great with my quail-egg sandwiches...

An animal which cannot, or will not, improve their body on their own, of their own volition, especially when they have a means of doing so is an animal, correct?

That would never make a difference to me.

Seems reminiscent of the "threads of fate" from "Wanted" (the movie where they curve bullets).

I am hesitant, however, to call the notion outright ridiculous...

My personal take on the theoretical utility of black holes? Blast 'em - find a means of destroying or destabilizing them - there's probably gold in them there black holes...