Acuario Rosa

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Interview with Diana Walstad

Acuario rosa:

Dear Ms. Walstad,

First of all thank you so much for accepting our invitation.

Diana Walstad:

You are very welcome.

Acuario rosa:

We would like to know how and when you got into this world of aquariums

Diana Walstad:

My mother always had aquariums and ponds. As a child during the 1950s, I was absolutely captivated by the fish. I kept tadpoles and Mosquitofish that I caught in agricultural canals. Later, I moved on to all kinds of tropical fish.
In 1988 after a long time without aquaria, I decided to once again set up a tank. This time I was determined to have a planted tank. (All past attempts to grow plants had failed miserably.) So I put a layer of potting soil layer under the gravel. When I got spectacular plant growth, I was inspired. I began researching the scientific literature and writing articles. In 1996 I started working on Ecology of the Planted Aquarium.

Acuario rosa:

How many aquariums do you keep actually? How much time a day you dedicate to maintain aquariums? Any High-tech aquarium?

Diana Walstad:

I have three tanks- two 55 gals and one 50 gal. I spend about an hour or two each week working on the tanks (i.e., cleaning filters and the glass covers, removing any algae, pruning plants, changing a little water, etc.). I used to do much less maintenance, but I have more time now.

I have no High-tech aquaria. Mine are all NPT (Natural Planted Tanks).

Acuario rosa:

your book “Ecology of the Planted Aquarium” is very well known, and a reference for lots of hobbyists, no matter if they keep low or high-tech aquariums. In the next questions I would like to dig a little bit on the ideas you published:

In the firsts pages of your book you write

“other hobbyists, mainly from Europe and within the last 20 years, developed techniques for growing plants in the aquarium that were highly successful. The sophisticated technology they used consistently produced beautiful, planted aquariums, which I will call “High-Tech” aquariums. The end result did, indeed, resemble “a slice of nature”. Unfortunately, the artificial methods to obtain such an aquarium ignored many of the natural processes of bacteria and plants. The end result –healthy fish and plants- resembled the natural, balanced aquarium, but the means to obtain it were unnatural, expensive, and labourious.”

Just after this paragraph you state

“The low tech aquariums that I maintain are characterized by a small or moderate number or fish, reduced filtration and cleaning, a large number of healthy growing plants, and diverse microorganisms. Essential to my natural aquariums is moderate lighting, a substrate enriched with ordinary soil, and well adapted plants. (…) At the same time it differs from the High-Tech tanks in that it takes greater advantage of natural processes. The low-tech aquarium is easier (and cheaper) to mantain. This is because natural processes are taking full advantage of. For example, bacteria and fish, not artificial CO2 injection – provide CO2 to plants. Plants -not trickle filters- remove ammonia from water and protect fish. Fish food and soil – not micronutrients fertilizers- provide trace elements.

Do you think that all kinds of plants can grow healthy in a natural aquarium? Which kind of plants better adapt to these kinds of aquariums?

Diana Walstad:

I do not know if all plants can grow well in an NPT. I have about 30-40 plant species doing well, and that is really enough for me. Some species will adapt better than others. Some do well for awhile and then do poorly later on. This is not surprising, as NPT ecosystems change over time.

In my 45 gal, the plants that did well during the 7 years I had this tank were various Cryptocoryne (C. balansae, C. wendtii, C. pondederiifolia, C. cordata), Echinodorus (E. tenellus, E. major), Sagittaria graminae, S. subulata, and Rotalia indica. Plants that died out were Ludwigia repens and Vallisneria.

Acuario rosa:

You priorize the stable and balanced aquarium, the search of a stable ecosystem in your tank with the only external addition of fish food and light, and a small power-head to keep a certain water movement. All the rest is kept untouched and allows almost no maintenance. Other “schools” in planted tank-keeping, specially in aquatic scaping, look for complex fertilizing routines, regular water-changes, pressurized CO2 injection, strong artificial lighting… do you think the same results are possible to be achieved with both methods? Do you see possible to grow an aquascape like the ones Mr Amano presents based on the “el natural” philosophy?

Diana Walstad:

No, I don’t think that the same results can be achieved by my methods and High-tech methods. The NPT develops naturally according to which plants grow well rather than a pre-determined plan.
The goal of an NPT is to have a tank with healthy plants and fish. What pleases my eye is naturalness more than art.

Acuario rosa:

The aquascaping hobbyists often try to keep carpets in their scapes, like Eleocharis Parvula, E.C. “Cuba”, Glossostigma Elatinoides… do you think is possible to achieve a thick carpet with your method? In case yes, which can be the receipt for achieving this?

Diana Walstad:

I have never tried these plant species.
Also, I’m not crazy about aquascaped tanks with a large, mono-species plant carpet. Too much open space. I do not think there is enough plant growth to support a heavy fish load or prevent algae.

Acuario rosa:

The method you describe in your book relies on a bacterial and fish source of CO2, coming from the bacterial activity and from the fish respiration. Do you think this source is strong enough to guarantee the levels of CO2 that some species require, for instance Hemianthus callitrichoides, Rotala wallichii or Rotala macrandra)?

Diana Walstad:

I have been able to grow Rotalia macrandra quite well in my tanks. I have not tried the other species. They might do better in High-tech tanks that provide high and consistent levels of CO2 and other nutrients. However, it is hard to say unless someone has actually tried to grow these plants in an NPT. One sure way to provide more CO2 for plants is to have plenty of fish. Recently, I have increased the fish load (and lighting) in my tanks. I am getting nice plant growth of more difficult species.

Acuario rosa:

In the last few years some aquatic scapers started to create not just “small submersed scapes”, but also to imitate terrestrial scapes. Mountains, forests, cascades, rivers, lonesome trees… What do you think about this new trend?

Diana Walstad:

Not much. I don’t understand why people would want to try to duplicate a terrestrial landscape in an aquarium. Trying to fulfill a predetermined artistic design is too rigid for my tastes. I prefer to watch natural interactions develop in the aquarium.

Acuario rosa:

Now please, explain in brief what the following words may suggest you:

TAKASHI AMANO- famous, artistic person

AQUATIC PLANT CENTRAL- nice place for information

AGA- good group of dedicated aquatic plant people

ADA- don’t what it is

ALGAE- part of nature

AQUASCAPING- landscape paintings in museums.

CONTESTS- keeps people enthusiased

Acuario rosa:

There are a lot of aquarium hobbyists that would like to make their first steps in the planted aquariums but find something like a wall that stops them: they think a big investment of time and equipment to maintain plants in the aquarium is needed. What would you recommend to a newcomer to avoid getting lost between all the information available of equipment needed (pressurized CO2, lighting and filtration systems…), dosing routines? What would you highlight as the basis for to keep a healthy planted aquarium? What is really essential for to keep plants?

Diana Walstad:

Adequate lighting, 2.5 cm underlayer of an unfertilized soil, large diversity of plant species, moderately hardwater, well-fed fish, and patience. Also, I would encourage hobbyists to buy my book rather than second-guess from what others have written.

Acuario rosa:

Which internet source of information (websites, forums, etc) would you recommend for learning more about aquatic plants and how to keep them? And for to understand better the behaviour of this ecosystem we try to keep in a glass tank, apart of your book (that we recommend to all hobbyists), which other book would you recommend to us?

Diana Walstad:I’m sure that there are many good books that I have not yet seen. The ones I happen to like best are mainly for plant identification:

A Fishkeeper’s Guide to Aquarium Plants by Barry James (nice, inexpensive book for beginners)

Aquarium Plants by Christel Kasselmann (expensive book for the dedicated)

Thank you for recommending my book. My book is now available as an e-book ($15 in English) that can be instantly downloaded from my book’s website:

My book sells very well in America, Europe, and Australia, but not in Spain, Portugal, or Latin America. I sincerely hope that this is a language barrier more than people buying pirated versions!

Interview and translation: Oriol Pascual
Management and publishing: Óscar Pereiro


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