Natural Aquariums
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from the Sep-Oct 1997 edition of The Aquatic Gardener

The low tech planted aquarium (which are commonly, and I prefer, to refer to as natural aquariums) is a viable alternative to consider when setting up a planted tank. I keep about 50 of them right now. I find they are easier and less expensive to maintain.

There are many benefits to the natural aquarium, they include; the lower cost of set up and maintenance, lack of equipment that must be learned to use and maintained, simplicity of set up, maintenance, and quietness. Also, in many ways, for me at least, instead of trying to force my will on a tank I feel more like I am providing the basic materials to allow the aquarium to grow and then attempting to gently guide it in the direction I would like it to take. I feel as though I have to work with what is within the aquarium, almost as if the interaction of the elements in the tank create their own unique personality and the survival and prosperity of the aquarium community becomes a cooperative effort between myself and it.

A natural aquarium by this definition is a very simple set up. The tanks I have are for the most part a glass container with gravel, plants, fish and often some small invertebrates. I use no filters in my tanks. Lighting is provided by either sunlight, shop lights, or the standard florescent aquarium hood. I use an air stone in a few tanks, those that house cichlids that destroy plants, and sometimes in special instances, such as in fry tanks. Most of my tanks don't have them.

There are good and bad points to different sizes of aquarium. Small aquariums and bowls, from 1 to 10 gallons, are very convenient for some breeding purposes, hatching some types of fish eggs, and isolating fish for various reasons. They are often available at local garage sales, second hand and thrift stores, and come in a variety of shapes. Because of their small size they can often easily be placed in a position where they are able to receive some sunlight making lighting easy. They also can look attractive around the house, used for accents in the way of potted houseplants. Aquariums in the 10 to 55 gallon range are in many ways the most convenient for practical purpose such as fish breeding. This size of tank is also easy to clean and move. They are also less expensive than the larger tanks and often easier to find space for. Larger tanks, 55 gallon and over, can make beautiful display tanks that can house more or larger fish. For attractiveness and number of decorating options, I believe the larger aquarium is the best choice.

I use a number of different substrates from blasting sand to various sizes aquarium gravel. I don't use additives to the substrate. I've tried laterite and saw no difference in plant growth. I did find that peat blocks worked nicely under Amazon swords but they have grown nicely in tanks without peat also. I tried using soil years ago and pretty much came up with a nasty stinky mess and have stayed clear of it since. I don't use liquid fertilizers or gravel additives. Plants receive nutrients through water changes and fish waste.

Lighting is the most important thing in a planted fish tank. The lighting and the choice of plants placed under it is for the most part the largest deciding factor in the success of the tank. In a natural aquarium I've found that you really can get too much light. This often causes outbreaks of algae.

Natural sunlight can be used effectively but should be somewhat filtered. Windows that don't get direct sunlight or only get a small amount or filtered sunlight should be safe. For windows receiving more sunlight a blind or sheer or lace curtain can be used.

Where natural sunlight isn't available and for the convenience of multiple tanks and shelves, shop lights are a practical solution. I always wanted a greenhouse to grow aquatic plants and fish in, but when we bought our house the room that was available was a work shop built on to the house. I was happy to have any room to myself for fish, but this one is really lacking in windows. So I use fluorescents shop lights in it. I use mostly 10 gallon aquariums. I prefer using two, 40 watt, cool white bulbs. They are usually inexpensive and seem to do the job.

I've found that with either natural sunlight or the shop lights that most aquarium plants can be grown. With the standard fluorescent hood lights that isn't the case and low level plants should be used. Amazon swords, Cryptocorynes, Anubias, Java moss and ferns, are all good low lever plants. I've also found Hornwort, Najas guadalupensis and Rotala indica to be able to grow in low light levels.

The amount of light a plant gets will effect the amount of growth, shape of leaves, length of space between leaves and color of plant. It also will effect the amount of algae growth in the tank. The combination of nutrients available for a plant, the types of plants, fish, invertebrates, water type, heat and frequency of water changes all contribute to the quality of the tank. The key to successful aquarium keeping is the ability to fine tune those items, whatever they may be, to work together.

The one item that is usually the most difficult to control is the type of water available. It is usually most convenient to use what comes out of the tap, unless you happen to have or can get an RO unit. The water here happens to have a high pH, usually between 8.0 and 8.3, in established tanks though, with peat or wood added it sometimes settled down to about 7.8. Without additives or bringing water in that's about as low as it gets.

Experimenting with different types of plants that have been shown to grow well in the sort of water conditions you are providing is the best way to find the plants that will do best. It's always good to at least have a general working knowledge of types of aquarium plants and the conditions they require. It's also helpful to know which plants aren't aquatics and won't live in an aquarium. Some of the plants sold in aquarium and pet stores are not. The best way to obtain this knowledge is by reading books on aquatic plants and learning over time.

Water changes are good for aquatic plants and fish, but there is a point where a tank can be over cleaned to the detriment of it's inhabitants. Natural waters are often filled with dietris, and mulm. The trick isn't in keeping a tank spotless, it's in achieving the correct balance of being clean enough to support the health of the animals and plants in it, but have enough nutrients in it to feed the plants and small organisms that keep it operational.

I think that it is reasonable to have some dietris build up between gravel in the aquarium on several conditions. First the gravel should not be allowed to become totally clogged. If it becomes black or foul smelling it should be cleaned. Mossy natural smells are normal for a healthy tank though. If the dietris or mulm is visible on top of the substrate it should be cleaned.

A simple tank cleaner can be made easily. A piece of plastic tubing from the hardware store, with a soda or other cleaned plastic container of appropriate size, can be cut in half and attached to the other end to serve as a vacuum. If a hole is cut in the top and used to attach the plastic tubing the container can be easily removed. It's like a vacuum with an attachment.

It seems a tank is often more successful sooner when it is started with easier plants and the more difficult to grow one's are added later. Similar to the concept of starting a new fish tank with hardier fish.

Each tank seems to have it's own personality and even in two tanks side by side I may not always be able to get the same plant to grow as well. The interaction of all the elements of the tank produces its own peculiarities. Often after having failed at growing a particular kind of plant several times I will go back to it after a year or two and have it grow fine.

I have noticed it being mentioned that non filtered aquariums should be stocked lightly. I haven't really found that to be a problem as long as appropriate regular water changes are carried out. Most of my tanks are pretty heavily stocked as I also breed most of my fish. I find that the number of water changes required for a tank depends on the planting and amount of light for those plants to grow, the number of fish, and more importantly the amount of feeding. In a heavily fed tank 30% once a week is almost too little, whereas in a very lightly fed tank once a month can suffice. It is however, almost always preferable to err by doing to many, rather than to few water changes.

I have really enjoyed working with the natural aquarium. I think that their relatively inexpensive set up cost and ease of upkeep, while still being able to maintain fish and plant health them a very good option for the aquarist.

This article, by me, appeared in the Sep-Oct 1997 edition of The Aquatic Gardener the publication of the Aquatic Gardeners Association

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