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14.15. Aquarium Aesthetics

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Author : David Bogert

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Time To Read :
7 minutes
Difficulty : Level 6

Excerpt :

Aquariums which follow the "rule of thirds" tend to be the most aesthetically pleasing.

Note the black hole in under the wood one third of the way in from the left and one third up from the bottom. We discuss this below under “Rule of Thirds”.

Aquarium Aesthetics

This is another one of those subjects which are just opinions. What I going to tell you here-in is just what appeals to my sense of aesthetics. Here is the list:

  • Background is always black paint on the outside of the back of the aquarium.
  • Substrate:
    • Fish Only Aquariums: Substrate is “natural” aquarium gravel of 1/8th to 1/4th inch size (3 to 6 mm) in shades of cream, tan, brown, and dark brown (always with under-gravel filters).
    • Planted Aquariums: Substrate is “natural” combination of: Black Diamond blasting media mixed with brown and dark brown coarse aquarium sand. Some of my planted tanks use “decking sand” that is a large particle sand with cream, tan and brown particles. And I have set up a planted aquarium with an under-gravel filter with brown oil absorbing fused clay product which is working very well.
  • No buddhas, shipwrecks, or other “unnatural” decorations
  • Only one type of rock and only one type of wood per aquarium. I never mix varieties
  • Rock and wood decorations generally follow the “rule of thirds”.

I found it interesting that Cory at Aquarium Co-op came out with a video where he basically outlined exactly what I have been doing for many years as to how he recommends the aesthetics be in an aquarium. I put Cory at the top as far as experts go in this hobby, so it was a great validation.

Wood and Rock in an Aquascape
2, Wood and Rock in an Aquascape

Note the path one third of the way in from the right. We discuss this below under “Rule of Thirds”.

Aquarium Backgrounds

“Backgrounds” are what is at the back of the aquarium. There are hundreds of ways to make aquarium backgrounds. There are YouTube videos on cement backgrounds, foam backgrounds, rock backgrounds, and purchased fake rock backgrounds (think $$$$$$). I’ve tried them all in my fifty years in the hobby.

And I keep coming back to a painted flat black background with all the tubes and equipment in the tank either basic black to begin with, or painted flat black. The idea is to make one’s fish and plants the centerpieces of the aquarium. Black backgrounds do that. Black backgrounds also allow algae to grow freely on the back surface without looking bad.

Iwagumi Planted Aquarium
Iwagumi Planted Aquarium

Note the small rock one third the size of the large rock, one third in from the right.  We discuss this below under “Rule of Thirds”.


I’ve tried white sand substrates repeatedly. I’ve always ended up replacing them with a “natural” coloration of substrate. I hate the look of feces floating over a bed of white sand. It is just well ….  yeeechhhhy. Surprisingly Black Diamond blasting media is almost as bad as white sand when it comes to appearances with time.


I like a natural look to my aquariums. So unnatural decorations have no place in my aquariums. So I don’t do buddhas, sunken wrecks or palaces. That is just my sense of aesthetics.

I do use a lot of plastic plants in my Lake Malawi Aquariums. There are some truly amazing plastic plants. Note I limit plastic plants to where the majority of the plastic plants are one variety, with some colorful accents here and there. I avoid a “montage” of many types of plastic plants.

Rocks and Wood

I try very hard to use only one type of wood or only one type of rock in any given aquarium. I hate the “busy” look of all sorts of rocks or wood. Again, that is just my aesthetic sense. I do mix rocks and wood in several aquariums.

Lava rock in the aquarium
Lava rock in the aquarium

Note the small rock one third the size of the large rock, one third in from the left.  We discuss this below under “Rule of Thirds”.

Rule of Thirds

I’m going to greatly simplify the “rule of thirds” here. The are YouTube videos that go into it in far more depth. Let us say one wants a basic rock theme in an aquarium. Select a large rock of the type you want. Then select another rock of the same variety which is one-third the size of the first rock.

Place the large rock one third in from one side. Place the other smaller rock such that the space between the two rocks is one third in from the other side of the aquarium. Then place smaller rocks around the two large ones if one so desires. This is VERY ROUGHLY what the “rule of thirds” is.

It states that any arrangement is more “pleasing to the eye” if the eye is drawn to a point one third in from one side and one third way up or down in any aquarium. This point can be a deep hole, a pathway ending, a piece of wood, or a rock.

Low Tech Planted Aquarium
Low Tech Planted Aquarium

In the aquarium above note that the pile of wood rocks and plants is one third in from the left side. It is not centered in the aquarium.

Note the rule of thirds is often modified in an infinite number of variations. Maybe there is only one large piece one third in from one side with a lot of other rocks around it. Or one pieces of stump where the main body is one third in from the side and the roots are all over the aquarium from there. The one common denominator is that the area the eye is drawn to is always one third of the way from one side of the aquarium. Most of the photos in this article have this feature.

Rule of Thirds
Rule of Thirds

The graphic above (from the YouTube Channel “The Water Box”) illustrates the Rule of Thirds quite well. The eye is drawn to the top of the wood one third in from the right and one third down from the top of the tank.

Aquascaping Guide – Rules of Thirds and Golden Ratio

The Rule of Thirds seems to give the aquarium a very natural look. The last thing that gives a natural look is three equal-sized piles of rocks placed equidistant across an aquarium. It ends up looking like soldiers in review. Hardly a “natural” look.

Questionable Aesthetics
Questionable Aesthetics

One very common “mistake” is to put one large rock or piece of wood centered in the middle of the aquarium. This might be aesthetic to the obsessive compulsive among us but most people do not like this aesthetic just because it is “unnatural”.

Wood pieces should be done the same way. Note that sometimes there is a large piece of wood that is just incredibly aesthetic which violates the “rule of thirds”. This points out that the “rule of thirds” should be termed the “suggestion of thirds”.

Also note that if the rock has a grain or striation to it the direction of the grain should agree for both large rocks.

Dutch Planted Aquarium
Dutch Planted Aquarium

Note the plant “pinnacle” one third in from the right and one third down from the top in the aquarium above. This follows the rule of thirds.

A Confession

Note that I would like to say these have always been my sense of aesthetics. But I have to admit that my first aquarium had a white Buddha, pink aquarium gravel and some downright psychedelic artificial “plants”. I pulled out the plants and the Buddha and hit them with bleach every two weeks.

This lasted a few months. Then I stopped fighting Mother Nature and went over to a completely natural look. And I’ve never looked back.

Amano Planted Aquarium
Amano Planted Aquarium

Note the path ending one third of the way in and one third of the way up on the aquarium above. This follows the “Rule of Thirds”.

Aquascaping Made Easy. 3 Simple Rules for Beautiful Aquariums