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15.16. Natural Aquarium

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Author : David Bogert

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Time To Read :
8 minutes

One interesting approach to planted aquariums is the “natural” approach. It attempts to duplicate a farm pond in an aquarium.

This “natural aquarium” can be defined by the following characteristics:

  • Heavily planted with lots of easy “green” plants
  • A few very small fish and/or shrimp
  • No filter
  • No air stone
  • No water changes.
  • Very light feeding
  • No fertilization
  • Various substrates
  • Plants are trimmed or harvested regularly

There are several YouTube presenters which have done “Natural” aquarium set-ups which meet the criteria above. These presenters include FlipAquatics, MD Fish Tanks, and Halfman Halfcichlid. There are also a bunch of presenters which have done small “natural” “nano” tanks.

The excellent YouTube channel “The Secret History Living in Your Aquarium” (Alexander Williamson) has several “natural” aquariums huge amounts of plants, a few fish, and no filtration with crystal clear water. He says he has done no water changes for years in these “natural” aquariums.

One of Alexander Williamson's Filterless "Natural" Aquariums
One of Alexander Williamson’s Filterless “Natural” Aquariums

Some of Mr. Williamson’s aquariums use “deep bed” substrates while others do not. Most of his tanks are “soiled” or “Walstad” tanks. Mr. Williamson has some small fish in these aquariums, typically with overgrowths of plants. There is no aeration and no water movement in these aquariums. Mr. Williamson does trim the plants and removes the trimmings. When he does that he is removing nitrates and phosphates from the aquariums.

These aquariums have crystal clear water. Mr. Williamson makes the point that these aquariums are somewhat “touchy” and cannot take much in the way of overfeeding or fish dying. If one is interested in this type of “natural” aquarium go to the “The Secret History Living in Your Aquarium” YouTube channel and browse.

This “natural” aquarium is supposedly a way to bring what is a farm pond into the aquarium. This type of “natural” aquarium, without filtration, is VERY difficult to do in an aquarium and kudos to Mr. Williamson for having accomplished it with some VERY attractive aquariums. I admit I’ve tried many times to get the “natural” aquarium and failed miserably every time. So I have some appreciation of how difficult it is.

"Natural" Aquarium
“Natural” Aquarium

“Balanced” Aquariums

Note that some try to come up with “balanced biotopes” aquariums (sometimes called a “balanced ecosphere”) where there is no inputs (i.e. food) and no outputs (i.e. plant trimmings). There are a few small fish, shrimp or snails in such a “balanced” aquarium. 

In theory the “balance” goes as follows:

  • Fish eat the plants
  • Fish excrete plant nutrients
  • Plants eat the nutrients
  • Fish eat the plants
  • etc.

These aquariums almost always end up as cloudy, unattractive beds of green algae. I’ve never run across a truly successful version of this extreme version of a “natural” fish aquarium. There are some nano tanks on YouTube that do this with shrimp or snails but none have fish. And all the ones I could find have cloudy, unattractive water.

"Natural" Aquarium
“Natural” Aquarium

Other Types of “Natural” Aquariums

Everyone has a different definition of what constitutes a “natural” aquarium. Some define it ONLY to describe an aquarium that meets the above criteria. I happen to be one of those who ascribe to that definition. Others define it simply as one of the many forms of low tech planted aquariums where there is no carbon dioxide injection and no fertilization by chemical fertilizers. Still others define it as a “mature” aquarium which has been inoculated with pond mud and the like.

Be that as it may, here are some other aquariums that are called “natural” by those who use them.

Ms. Walstad and her Aquarium
Ms. Walstad and her Aquarium

Walstad “Natural Aquariums”

There is a type of “natural” aquarium which differs from the above. This is the Walstad soiled aquarium.

This can be defined by the following characteristics:

  • Heavily planted with lots of easy “green” plants
  • A few very small fish and/or shrimp Some small Fish
  • No filter Limited Filtration
  • No air stone
  • No water changes. Small Water Changes
  • Very light feeding  Over Feeding
  • No fertilization Fertilization from excess food
  • Various substrates One inch (2.5 cm) cellulose rich soil under one inch gravel

We cover that aquarium form in this article:

15.8. Walstad Aquarium

"Natural" Aquarium
“Natural” Aquarium

Father Fish “Natural” Aquariums

Another system that uses a filtered “natural” planted system with some air stone aeration can be perused in the popular YouTube channel “Father Fish” (great YouTube channel, even if, like all of us “older” folks, he tends to ramble on a bit). The system he uses is somewhat different than most low-tech planted approaches and radically different than the high-tech planted approaches.

The system he uses can be summarized as follows:

  • Heavily planted with lots of easy “green” plants
  • A few very small fish and/or shrimp Light stocking of medium sized fish
  • No filter “Deep substrate”, “detritus” and plant filtration
  • No air stone  Small air stone or no air stone
  • No water changes.  No water changes
  • Very light feeding   Very small feeding
  • No fertilization  Fertilization only from food and compost substrate
  • Various substrates Rich compost under three inches of sand

Father Fish used an organic deep sand bed in what appeared to be about one hundred heavily stocked fish aquariums in his store (it is now closed). Father Fish added a whole bunch of “stuff” to very organic potting soil (looks like African violet mix to me). He used one inch of this soil mix for the first inch in his deep sand bed planted low tech aquariums.

"Father Fish" Aquarium
“Father Fish” and one of his Aquariums

He added worm castings, peat moss, Black Kow compost, blood meal, organic snail food, iron supplement, Osmocote, lime, and Epsom salts. He then added three to four inches of sand over that mix. He inoculates  the aquariums with pond mud. Father Fish calls this a “natural” aquarium.

Father Fish has used this method for his many low tech planted aquariums. The lower three inches of the substrate in all his tanks is dark black in color from humus.  His filters are sumps with five inch deep sand beds in them. The ammonia and dissolved organic compounds (DOCs) are consumed by mulm and detritus in the above the sand. The mulm and detritus, in turn, is consumed by a whole host of tiny critters that Father Fish introduces with his pond mud inoculate.

It appears Father Fish is doing most of his biofiltration inside his aquariums with the surfaces of plants, detritus, substrate and decorations. Father Fish has some very healthy fish and some very healthy plants so his methods work. Just make sure the sand is at least three inches deep. If you try to cut back on this thickness, one can end up with a smelly cesspool.

"Natural" Aquarium
“Natural” Aquarium

Dan Hiteshew Aquarium

Dan Hiteshew on his site “Everyday Fishkeeping” (good YouTube channel) has some fish tanks using what he calls a “natural” approach.

The system he uses can be summarized as follows:

  • Heavily planted with lots of easy “green” plants
  • A few very small fish and/or shrimp Moderate number of fish
  • No filter Limited “Detritus” and Plant Filtration with small filter with poor media
  • No air stone Small Air Stone
  • No water changes. Sizable Water Changes
  • Very light feeding  Decent Feeding
  • No fertilization  Fertilization only from food
  • Various substrates Deep gravel substrate
Dan's "Mature" Aquarium
Dan’s “Mature” Aquarium

Dan Hiteshew espouses aquarium filtration by something he calls a “deep gravel filter”. It is simply a three to five inch deep bed of aquarium gravel. This gravel bed will accumulate a thick biofloc in the spaces between the gravel stones. This biofloc can accumulate sizable amounts of nitrate in its structure as “assimilatory denitrification”. And it can foster a good growth of easy to grow “green” plants.

This 125 gallon (473 liter) does have a Sunsun 304B filter loaded with bioballs and ceramic rings on it. But this is very poor biofiltration for this stocking of a 125 gallon (473 liter) aquarium (Dan admits it is poor filtration). Dan uses inoculate from ponds and thus this aquarium is very “mature”. Note the green Java fern, anubias and brown Buce pictured in Dan’s tank above will grow anywhere.

"Natural" Aquarium
“Natural” Aquarium

This all shows that there are MANY ways to be successful at keeping aquariums.

For both the Father Fish and the Dan Hiteshew methods I would add a ton of filtration to the mix. Something along the lines of a large canister filled with foam, pot scrubbers or K1. Or a sump. And I would baffle the outlet of the filter to minimize the surface agitation in the aquarium. I’m just a huge believer in over filtration in ANY and ALL tanks.