1) The Rule of Thirds

The “Rule of Thirds” is a visual arts composition technique. The idea is to avoid placing the aquarium's focus in the center. When the focus is in the center, viewers tend not to see the entire aquarium. By placing emphasis points away from the center, the viewer will notice the entire aquarium.

The “thirds” refers to sectioning the visual display—the aquarium in this case—into thirds. Placing key corals, decoration, and plants in these intersections will make your aquarium more pleasing to the eye. Some take this very literally and apply masking tape to the front glass in the pattern of a Tic Tac Toe board. The intersections of the tape lines are good places to put key decorations.

2) Background

An aquarium background is an absolute must-have for an attractive aquascape. Black backgrounds help you focus on the tank's contents while visually hiding equipment and cords behind the aquarium.

You may also like frosted or white backgrounds, but keep in mind these colors only look good if you religiously clean the back glass. Black is the most forgiving when it comes to cleaning.

3) Space

You may be tempted to fill an aquarium with rocks, plants, and coral. It often looks much better to leave open space in an aquarium. This provides visual contrast and space for fish to swim.

A good rule is to aim to have at least as much open space as hardscape (rock and wood). Plants and corals will grow to fill more space over time, so give yourself a good buffer.

4) Scale

When you put a big fish (or a small fish that will become a big fish) into a small tank, it makes the tank feel small. With this in mind, smaller fish make aquariums feel larger, as do fine gravel, plants with small leaves, thin branched wood, small polyp coral, and thin branched corals.

Many people want their tank to feel massive, and choosing small fish and smaller aquascaping structures can create that effect.

Other times you may want to make a desk tank feel exceptionally small. Choosing larger gravel, rocks, and large-leafed plants will achieve that effect.

5) Color

Contrast can help to exaggerate the colors of your fish, coral, and plants. In reef aquariums, avoid placing all your green corals together, blue corals together, or orange corals together; instead, try to intersperse the colors.

In planted aquariums, look for plants in different shades of green, or even red and purple. It can help to look at a color wheel to remind yourself of complementary and supplementary colors. Also consider fish like cardinals or neon tetras. Red and blue are an excellent contrast against the predominantly green background of most planted aquariums.

6) Shape

Just as color contrast can be good, shape contrast can make your aquarium much more interesting. In reef tanks, try to incorporate encrusting, branching, and plating corals. Any tank dominated by only one type can be visually boring.

In planted aquariums, try mixing round, broad-leafed plants with thin-leafed plants. Mix tall plants with shorter plants.

7) Lighting

Omnidirectional lighting from fluorescent lights can make an aquarium look flat or still. Point-source lights such as those from Kessil can add depth and glitter lines that bounce off moving water, making the tank feel alive. If replacing your light fixture isn't an option, adding extra surface movement can increase the number of glitter lines. You can also get creative by highlighting structures and even specific corals or plants with spotlight-style effects.

Lights with adjustable colors, such as the Kessil LEDs, Fluval Marine & Reef LEDs, Fluval Fresh & Plant LEDs and Ecotech Marine Radion will allow you to adjust the light spectrum to suit your desired aesthetics. Bluer lights help bring out green, yellow, and fluorescent colors, while warm yellow light can increase blue and purple colors.

8) Movement

When an aquarium is too still, it can look dead. Adding water movement, along with plants or corals that sway with the current, can add more visual interest.

Fish also provide movement, but not all fish do so equally. In freshwater, your plecostomus may move only a little every couple of minutes, so it may be good to include an active fish, such as a rainbow fish.

In saltwater, anthias, tangs, and chromis move a lot, while fish like groupers, eels, and jawfish can sit still for long periods.

9) Equipment

Many great aquascapers believe anything that distracts from the aquascape should be removed. With this in mind, work to eliminate all equipment from view, or make it as attractive as possible.

In freshwater, power filters and heaters in the tank can be unattractive. Canister filters, inline heaters, and CO2 reactors reduce clutter in the tank. Better yet, look for integrated equipment. The OASE BioMaster Thermo Canister Filters include an integrated heater. To the Fluval Filters and the OASE Filters, you can add an inline UV sterilizer (see OASE ClearTronic UVC 7W UV Clarifier).

In saltwater, you can use a sump to hide your protein skimmer, filtration media, thermometer, heater, pumps, and more. Consider closed loops or creative solutions like the Tunze Nanostream Rocks to hide your pumps.

10) Maintenance

Your aquascape doesn’t just need to look good; it needs to keep looking good. Make sure you leave plenty of room to clean. Avoid placing large amounts of rocks flat on the bottom of the tank. This can lead to excessive detritus buildup.

Make sure that there is enough room between the glass and the hardscape to fit your hands in to clean.

Keep in mind it is nearly impossible to gravel-vac super-fine substrates.

Pale or white rocks and decorations will need to be meticulously cleaned to keep them looking attractive.