How to aquascape small tanks


James Starr-Marshall looks at some of the key creative and technical aspects of effective nano and pico aquascaping.

As science advances and technology develops, the products we use every day are inevitably miniaturised — and aquariums are no exception.

We can keep ever smaller aquariums, with tanks less than 20 l/4.4 gal being aquascaped to a high standard and kept long-term stable and healthy.  There are limitations concerning plant and fish/shrimp species but, as long as rules on stocking fauna are sensibly followed, a tiny aquascape can offer interesting possibilities.

The fishkeeper choosing nano or pico scaping enjoys many benefits.

Budget is always a concern with planted tanks, so reducing aquarium size also reduces the cost of equipment and additives and with living space for everyone at a premium a small aquarium makes aquascaping more accessible to all.

Illusion of space

Nano and pico aquascapes can have unique appeal, drawing the eye to an encapsulated world and convincing the viewer that the aquarium is larger than it is.

The traditional method of planting is to place the smallest at the front and progressively larger plants towards the back. This makes practical sense, as larger plants can be more easily seen. However, in smaller aquariums, this often serves to foreshorten the aquascape, making it appear flat.

Try smaller leaved plants towards the back and larger leaved varieties towards the front. This appears that perspective is making the leaves in the distance appear smaller.

Also helpful in adding apparent depth is the suggestion of a vanishing point, such as a tapered sand pathway running from front to back. The converging edges of the path lead the eye to believe that it is disappearing into the distance.

Aquascapes in larger aquariums can be arranged with numerous varieties of plants. In a nano or pico tank, however, such a display can appear crowded and messy. Limit the number of plant species as your tank size reduces.

Creative options

There are several prescribed styles such as Iwagumi or Wabi-Kusa and these dictate, to varying extents, what an aquascaper can or cannot do.

For the beginner the rules of any chosen style will act as a guide through which to learn about composition, form, texture and colour. For the advanced scaper there’s the challenge of producing a beautiful, original aquascape while still conforming to criteria.

Some aquascapers bend and break rules and innovate. Others prefer complete freedom and create something more abstract.

Artistic licence

A growing trend is to take inspiration from the natural landscape, which may seem strange as the scape is submerged. However, humans do not frequently observe underwater scenes, so it is more productive for an aquascaper to look to the nature as seen every day.

How the aquascaper chooses to interpret a scene is very interesting. Most set out to capture a slice of nature, but what each decides to include varies greatly. Add each scaper’s choice on which plants, rocks and wood best represent key features and the aquascape becomes personally stylised.

Transposing landscape to aquascape takes licence. Grass cannot be recreated by Eleocharis or Lilaeopsis as they will grow too tall. Alternatives must be found and nano and pico aquascaping becomes an area where size fuels rather than stifles creativity.

Compare the styles of tank

The 20 l/4.4 gal aquascape featured in the main picture is a stylised interpretation of terrain around the foothills of the Dolomite mountains in Italy.

1. False perspective

The scaping of this 20 l/4.4 gal tank was an experiment in false perspectives — the idea being that the continuation of the lines struck by the angular rocks would add to the feeling of depth. To some extent this has worked, but the scape looks awkward and unnatural.

2. Soft appearance

This is the second version of the same aquascape. An attempt has been made to soften its appearance. Again this has worked to some extent, but overall depth of field is greatly reduced, despite the inclusion of a tapered sand pathway.

How to start aquascaping

Before setting up a planted tank consider what you want. Do you want an aquascape that comes to fruition quickly? Or would you prefer an aquascape that matures gradually, offering lasting pleasure?

Hi tech v. low tech

In hi-tech planted tanks, light, CO2 and nutrients are supplied in abundance. The plants grow fast and need regular pruning and water changes.

Lighting will be far less intense in a low-tech equivalent. Smaller quantities of nutrients can be added, reducing the need for such regular changes, and CO2 can be kept to a minimum or replaced with liquid carbon additives.

The smaller a volume of water the less stable it will be. Any substance added must be in scaled-down proportions. Much accuracy is required when adjusting the CO2 rate or dosing liquid carbon.


A pressurised CO2 system is worthwhile and essential with very bright lighting. Under strong lights your plants will demand lots of CO2, which in small tanks leaves little margin for error.

If the lights fail to switch on, or you prune plants too heavily, CO2 can quickly reach lethal levels for fish and shrimps. Get experience before embarking on a hi-tech planted nano and even more for a pico aquarium. If opting for lower lighting levels then CO2 can be added more slowly, posing less risk.


A high or low-tech system demands good filtration if you intend keeping fish or shrimps.

In the planted tank lots of biological media and a high turnover rate will be useful tools against algae. For a nano or pico, the external hang-on-back filter is usually most appropriate as models are smaller than canisters and still sit outside the tank. However the outlet cannot be positioned independently of the inlet, making ideal circulation difficult.

External canisters have a separate inlet and outlet, which, combined with extra capacity for media, make them excellent. However, the smallest canisters can turn over at least 300 l/66 gal per hour, which can uproot plants and disturb the substrate in very small tanks.

Consider the spread of flow leaving the outlet and using an oversized outlet nozzle or drilling lots more holes in the spray bar is often helpful.


A high nutrient substrate is the basis for healthy plant growth. It will ensure the roots are supplied with what they need where they need it and that the water column is never devoid of nutrients.

Nutrients should be dosed regularly to the water in excess of the plant’s requirements to combat algae. Such excess can be prevented from building up too much by regular water changes.


Formulae of varying complexity can work out how much light you will need in watts per gallon for a certain size of tank. It’s almost impossible to incorporate all the factors that influence how much light reaches the plants, so these figures are only a rough guide.

Often overlooked is the height at which the light sits above the aquarium. Raising the lamp an extra 7.6cm/3” above the surface can reduce intensity reaching the tank base by more than 50%.

This can be advantageous to the nano or pico scaper. Instead of raising CO2 levels to match the plants’ demand, the lamp can be raised in height until demand for CO2 matches supply.

Adjustable height is the reason I’ve started using desk lamps for nano and pico aquariums. I tend to use those with a 12v 20w halogen bulb for tanks up to 8 l/ 1.8 gal and 35w bulb for tanks to 16 l/3.5 gal.

Set up a budget plant-only pico

1. Adding substrate and hardscape

ADA aquasoil substrate was added to a 150mm/6” glass cube vase, four fragments of slate were used for the main formation and two pieces of lava rock added to grow Riccia on. Last addition was cosmetic sand. I removed some aquasoil with a teaspoon and replaced it with aquarium sand. I then soft brushed all the substrate into the desired shape.

2. Preparation and planting

I soaked the substrate with a spray bottle, keeping plants wet throughout. Riccia fluitans was tied to lava rock with fishing line and placed behind the main stones. Staurogyne sp. and Hemianthus callitrichoides were planted with tweezers. HC is often planted in clumps attached to rockwool, but this displaces too much substrate. It’s best in individual plantlets.

3. Filling and setting lighting levels

I filled via an air line hose from a bottle of dechlorinated tapwater. As the tank is too small for fish or shrimps I decided against a filter. Instead I did a daily 80% water change just before switching the lights on. The tank was lit six hours a day by a 20w halogen desk lamp positioned 125mm/5” above the surface. I used Flourish Excel and ADA fertilisers daily.

4. Checking progress

Despite deciding against CO2 or having a filter for this set-up all the plants grew well and were without algae issues. After eight weeks the aquascape had matured nicely and, at around £40 for a total outlay, I was delighted with the finished article! I felt as if I had met my personal challenge of creating the illusion of space when there really wasn’t any.

Pico tank on a budget

Tank: 150mm/6” glass cube vase from florists £9

Lighting: 20w desk lamp from supermarket £7

ADA Aquasoil: £2.85

Plants: (three pots, £5 each, for two tanks) £7.50

Hardscape: from fish shop £0.75

Easy life Easy Carbo: 250ml £5.99

Tropica Plant Nutrition+: 100ml £6.95

Total: £40.04

Q and A

Graeme Edwards, founder of the UK Aquatic Plant Society, advises on plant choice and care for maintaining a 10 l/2.2 gal aquarium.

Can you recommend a good stem plant?

I suggest Myriophyllum mezianum, Rotala wallichii and Rotala nanjenshan. Due to their fine needle leaves, these look great even in the smallest tanks. I would choose Micranthemum umbrosum as this delicate plant has beautiful round pearl-like leaves and is a vibrant green.

Does Micranthemum umbrosum need any special care?

Give it a nutrient rich substrate and daily dosing along with CO2 and you will be pruning almost weekly. Lighting requirements are moderate, around 1-2w per gallon. When trimming this plant start low and shape it more each time you trim.

What carpeting plant would be most appropriate?

The most obvious would be Hemianthus callitrichoides ‘cuba’ (HC). Its tiny leaf structure, dense carpeting and ease of maintenance is very appealing.

How best do I prune HC in smaller tanks?

For trimming you only need sharp scissors. This enables you to create pleasing curves. Prune back hard every time to give dense growth and longevity to the carpet.

Which aquatic moss would look best on this scale?

I suggest mini Java moss (Taxiphyllum sp). You may find it easier to get Taxiphyllum barbieri which is just as beautiful. All mosses will give scale and sense of age to any nano aquarium.

What is your favoured method of attaching moss to wood?

I spread very thin to see the wood clearly through it, then simply tie it down with cotton.

If laid too thick the moss underneath will often die, due to lack of light, water flow and nutrients. This results in a localised ammonia spike which gives seed to hair algae among the moss. The key with most mosses is regular pruning.

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