Paludarium Building Guide — Where Aquatic & Terrestrial Plants Coexist

A paludarium is a hybrid layout that combines aquatic plants and terrestrial plants in a single tank or container, merging aquarium and terrarium concepts. Waterfalls, streams mimicking mountain creeks, moss-covered rock faces, and aquatic plants emerging above the waterline -- paludariums recreate waterside landscapes from nature indoors. Their popularity has surged recently through social media, and they are attracting attention as a new way for aquatic plant enthusiasts to enjoy the hobby. Here we explain the basic steps for creating a paludarium.

Types and Characteristics of Paludariums

There are several styles of paludariums, and the design differs depending on the direction you want to take.

The open aquarium style lowers the water level in a standard aquarium tank and lets driftwood and rocks protrude above the water surface. Moss and emersed plant growth are established on the exposed portions to create a terrestrial feel. Since you can use existing aquarium equipment as-is, this is the most approachable type.

The wall-type paludarium uses expanding foam or cork bark to build up the back wall, into which epiphytic plants are planted. Because vertical surfaces are utilized effectively, deep and dimensional scenery can be created. Construction requires skill, but the completed impact is dramatic.

The waterfall/stream type uses a submersible pump to draw water up and flow it over the terrestrial section, recreating waterfalls or small streams. The addition of water sounds and movement brings a sense of presence that other types cannot match.

The terrarium-based type uses a glass terrarium case with a shallow water area at the bottom. Terrestrial plants are the main feature, with the aquatic portion playing a supporting role. This style is ideal for cultivating humidity-loving tropical plants.

Required Equipment and Container Selection

The base container for a paludarium is typically a glass case with height. Since both underwater and above-water sections need to be accommodated, more height is needed than a standard aquarium tank. Starting with a size of about 30-45 cm wide and 30-45 cm tall makes it manageable.

Lighting needs to cover both underwater and terrestrial areas. Aquarium LEDs can work, but adjust position and angle to ensure adequate light reaches the terrestrial plants as well. Pendant-style lights offer easy height adjustment and suit paludariums well.

Filters for paludariums with limited water volume should be hang-on-back or small canister filters. Using a submersible pump to circulate water can serve double duty as both filter and waterfall flow.

A misting system (fog generator) makes humidity maintenance for the terrestrial section dramatically easier. Setting a timer to automatically spray mist several times daily greatly reduces management effort. If misting manually, twice daily -- morning and evening -- is a good target.

For heating, install a standard aquarium heater in the underwater section. Maintaining water temperature around 25 degrees Celsius in winter keeps both aquatic and terrestrial plants growing healthily.

Building the Layout Structure

The most important aspect of a paludarium layout is the design of the boundary (shoreline) between the underwater and above-water sections. How naturally you can recreate the water's edge largely determines the quality of the finished piece.

As a basic structure, first lay substrate or gravel on the bottom and create a slope on one side to form the land area. Use rocks and driftwood along the slope as retaining walls, filling gaps with substrate or sphagnum moss to create planting pockets for terrestrial plants.

Positioning driftwood so it bridges from underwater to above water creates natural continuity. Branching driftwood serves as footholds for epiphytic plants and forms the skeleton of the layout. For rock arrangements, lava rock and mountain stone (seiryu stone) are standards, and choosing materials with textured surfaces that mosses and plants can attach to is important.

To create a waterfall, hide a submersible pump beneath the land area and run tubing to carry water up to a high point and let it flow down. Creating the water path with flat stones produces a thin film of water spreading beautifully. How well the tubing is concealed directly affects the visual appeal, so covering it with rocks and plants is essential.

For the terrestrial soil, a moisture-retentive mix of akadama soil, peat moss, and vermiculite works well. Covering with sphagnum moss prevents drying and promotes moss establishment.

Selecting Aquatic and Terrestrial Plants

In a paludarium, choose plants suited to each zone: underwater, waterline, and above water.

For the underwater section, shade-tolerant epiphytic aquatic plants such as Anubias nana, Microsorum, and Bucephalandra are recommended. These grow without CO2 injection and create a natural atmosphere when attached to driftwood and rocks.

For the waterline, mosses like willow moss and flame moss that grow both submerged and emersed are ideal. Covering the boundary between water and land with moss creates a natural-looking transition. Planting emersed forms of Hygrophila and Rotala along the water's edge is also effective.

The terrestrial section suits humidity-loving tropical plants. Fittonia (nerve plant) is a standard choice, offering rich colors and easy care. Selaginella (spike moss) has delicate foliage resembling true moss and grows vigorously in moist environments. Small ferns and Begonia species (wild types) also excel at creating atmosphere.

For epiphytes, small Tillandsia species and Lemmaphyllum microphyllum can be attached to driftwood and walls. Ultra-small epiphytic orchids such as Lepanthes and Pleurothallis are also popular as accents for advanced hobbyists.

Daily Paludarium Maintenance

Paludarium maintenance differs from standard aquarium care in several ways.

Water level management is most critical. Since evaporation lowers the water level easily, check every 2-3 days and top up as needed. Use dechlorinated water at matching temperature when refilling.

Humidity management is handled through misting or a misting system. If the terrestrial section dries out, mosses and epiphytic plants will die, so aim to maintain 60-80% humidity. However, excessive moisture causes mold, so ensure moderate ventilation as well.

Water changes should be done weekly at 20-30% of volume given the limited water quantity. Use a pipette or syringe to remove water from the aquatic section and replace with fresh water. Clean areas where debris tends to accumulate by suctioning with a pipette.

Trim terrestrial plants as their growth demands. Fast-growing plants like Fittonia need regular cutting back to maintain layout balance. Promptly remove dead leaves to eliminate potential sources of mold.

Aquatic plants for paludariums can be found on Botachoku. Plants shipped in emersed form are especially convenient, as they can be used directly in the waterline area of a paludarium. If you let the grower know you plan to use them in a paludarium, they can suggest suitable species.