"Biologically mature"

[sharkweek178]

I see the term "biologically mature". Don't add this fish until the tank is biologically mature. I get the concept in that some fish are sensitive to swings in water parameters. I never see it defined very well. Does that mean after the tank is cycled? Is it after fish have lived in it for a while? What is a good definition?

 

[Essjay]

It is usually defined as a tank that has been running with fish trouble free for 6 months.

We concentrate on growing micro-organisms which remove ammonia and nitrite from the water as those substances are killers. But there is a whole host of other micro-organisms, and some not so micro, which grow in a fish tank over time. These all help to stabilise water parameters and conditions, and are not likely to be present as soon a cycle, fish in or fishless, has completed.

 

[Magnum Man]

I would think after the beneficial bacteria form, & there is a sufficient Bio film on most interior surfaces... some of the specialized Oto's mostly eat bio film, so they would definitely need a "mature" tank

 

[Byron]

The substrate is the "bed" of a healthy established aquarium. Once it is running, as essjay noted, various species of bacteria beyond the common nitrifiers will colonize especially the substrate, and form the basis of a stable biological system. This is why the substrat is so important. All else being equal, you can forget a filter, but you cannot forget a good substrate.

I took nitrate and pH readings twice a week for a few weeks, then every week just prior to the water change, then a couple times a month. Over a period of 12 years, the readings for each of the tanks in my fish room were the same, always. Nitrate was in the 0 to 5 ppm range using the API liquid test, and pH never varied in any one of the tanks by more than 1 or 2 decimal points. This is stability. Each tank's pH was a bit different, even though maintenance was the same, water the same, fish load basically the same, and lots of plants. Each tank established its own biological system. The water change was 60-70% once a week. The parameters never changed.

 

[GaryE]

It's a vague term. Cycled and colonized with live plants, algae (preferably not running wild, but present) and a host of micro-organisms would define it for me. It bothers clean freaks, as a too clean aquarium is a deathtrap for fish, as much as a filthy one is.

 

[gilpi]

The filter is where most of your beneficial bacteria lives, not too many people talk about this anymore. When you cycle a tank, you’re basically cycling the filter or maturing it till it’s safe to add fish. The bacteria, once it has flourish, needs the water passing through it, one of the reasons you do not replace the filter media, simply rinse it and back into the filter it goes. Good luck!

 

[Byron]

The filter is where most of your beneficial bacteria lives, not too many people talk about this anymore. When you cycle a tank, you’re basically cycling the filter or maturing it till it’s safe to add fish. The bacteria, once it has flourish, needs the water passing through it, one of the reasons you do not replace the filter media, simply rinse it and back into the filter it goes. Good luck!

This is relevant to the nitrifying bacteria, but an "established tank" is beyond this bacteria. The waste-eating bacteria do not live primarily in the filter but in the substrate, and they are even more important than the nitrifiers in some ways. An established tank is one where the substrate is established, and it takes a few months under normal conditions. These bacteria affect water quality not with respect just to ammonia and nitrite, but nitrate as well as the other pollutants that cannot be processed without them or without water changes.