Have you ever considered the "lifetime" of an aquarium?
Aquariums are very much like terrestrial gardens. They have 'ebb and flow" (literally, in some cases!), growth, challenges, and dieback..they have setbacks- and rebounds. I'll bet that if you tracked what happened in a "community aquarium" over the course of say, two years, what you end up with after two years may be significantly different than what you started with.
Oh, sure, some of the changes that occur during the "life" of an aquarium are human-imposed, such as equipment modifications/replacements, aquascaping "edits", fish and plant additions, etc. However, if you look carefully (as I'm sure that you do), as many changes can be attributed to the cycle of life as to human "intervention" of the aquarium environment.
Things like the growth and/or "dieback" of plants, the proliferation of algae, the gradual decay of wood and aquatic botanicals, social hierarchies among inhabitants, the "patina" of biofilm/algae, however subtle, that makes fresh aquarium substrate "matte out" over time, looking more natural, more subtle...more full of life. What the Japanese call "wabi-sabi"- the transient nature of things- is both beautiful and inevitable.
I remember from my experience growing corals commercially, that on any given day, some of the many thousands of specimens we had growing in our facility would be struggling. Some would be absolutely cranking! Others would be just sort of "there." And it would change constantly. It was a great demonstration for me on what aquatic husbandry is all about. The science is one thing. You learn "best practices" and protocols very quickly, and adhere to them. The "art" of being an aquarist- the really tricky part of this game- is how we choose to manage this multifaceted microcosm, with all of its "moving parts" and subtle complexities.
We can let things decline. Or, we can take charge and attempt to stave off the inevitable.
How we as humans choose to accept this progression and change is purely based on our own tastes. The reality is that these things will continue despite any interventions we perform on our tanks. We can "resist" them, performing "maintenance" takes on our tanks, like trimming plants, fragging corals, scraping algae, stirring the top layers of substrate, etc.- but these are merely serving to counteract or stave off the inevitable changes that occur in an aquarium as it establishes itself, begins to thrive, and gradually declines. Of course, in many cases, the "decline" is so gradual, so subtle, that the outsider hardly notices. You, the aquarist, ever keen on anything that occurs in your tank, will notice- and often perform subtle (or not-so-subtle) interventions to counteract this process.
I sometimes wonder what our aquariums would evolve into over the course of a couple of years if we merely performed basic maintenance tasks, such as water changes, equipment maintenance, feeding, scraping the viewing panels, etc., and did little else. No animal replacement. No trimming of plants, fragging of corals, or removal of fish fry. No rearranging of the aquascape.
What would you end up with? Could you resist "editing" your aquarium for a period of time? Would you want to? Is this as much part of the hobby as just looking into the tank and enjoying it? Would anarchy reign if you left the tank to its "own devices", or would a different sort of system evolve? Would it succeed on some level that you wouldn't have considered previously? What would come to dominate, and what would fade away? How would nature work with what you gave her in your little glass or acrylic world called "an aquarium?"
Fun to ponder. Perhaps.
Stay thoughtful. Stay engaged. Stay full of wonder.
And Stay Wet.