Join Date: Aug 2015
Location: Milky Way Galaxy
In natural ecosystems, though, there are a lot of factors at work that we avoid in our tanks. For example, high nutrient levels lead to algae blooms. We treat our algae blooms. Fish can migrate within a water system to cleaner water if flow slows in a natural system--in our tanks they are confined to a small (for them) box. Flowing water goes through natural filtration--densely grassed marshes and wetlands, for example--that still water in our tanks cannot mimic. Many streams are spring-fed, meaning the water comes to surface from underground aquifers that naturally filter the water to some extent--and lakes are stream-fed, often. There are many 'natural' filtration systems that take place in nature. Sure, some species may be adapted to truly still water, but I would think those are in a minority. Nature has many methods of filtration.