of glass or acrylic (with silicone) to create underwater towers. As an alternative to islands, you can add a shelf by attaching a panel of glass or Plexiglas‚ to the back or sides of the tank using silicone. As with an aquarium, the water area needs to have good filtration and live plants. With island aquaria, large sponge filters or submersible filters are most effective because the low water level is unsuited for external, hanging-type power filters.
Island aquaria are half-filled tanks with islands made of stacked wood or rocks or wedged cork bark.
Plant Selection
Because most aquatic amphibians do not like bright lights, you will do best with aquatic plants that thrive in low to moderate light levels; many are listed on the next page.
Background Plants
These plants are likely to grow as tall as the height of your aquarium, creating a beautiful, naturalistic background. In some designs, you can place one or more tall plants in the middle of the floor plan to add another visual dimension to the tank. Newts and frogs will use tall plants for climbing or resting near the water surface and also as egg-laying sites. Among the best choices tested and proven with the species in this book are: water wisteria (Hygrophila difformis), elodea (E. Densa), Sagittaria spp. (S. subulata, S. graminea, and others), Vallisneria spp. (the ribbon-leafed V. spiralis and the twisted-leafed V. tortifolia), large Amazon swords, and tall Cryptocoryne spp. (C. balansae, C. ciliata, C. retrospiralis).
When growing plants hydro-ponically in gravel, they must be cleaned of any soil before being added to the substrate.
With bunch-type stem plants, such as water wisteria and elodea, regular pruning and pinching keeps plants controlled and bushy. Insert the cut sections in gravel to produce additional plants. Rosette- or ribbon-forming plants, such as Sagittaria spp., Vallisneria spp., and sword plants, will produce runners.
Midlevel Plants
These plants typically grow a quarter to half the height of the aquarium and are best planted in the middle areas of the floor substrate. Good species are medium Cryptocoryne (C. affinis and C. blassii), medium Sagittaria spp., smaller sword plants, and Anubias spp. (A. afzelii, A. barteri sub-species and varieties, and A. gracilis).
Foreground Plants
Plants for the tank foreground must be small so that they do not block the view. Most commonly used species spread by runners and form a short, green, growing carpet. The best is dwarf Sagittaria sp., which performs exceptionally well in my tanks. Dwarf sword plants (E. tenellus and E. quadricostatus) require more light but also thrive. The smallest of the genus Cryptocoryne, such as the dwarf forms of C. nevillii and C. wendtii, are good choices and eventually give the appearance of a tall grass field. Although there are many other good foreground plants sold in aquarium stores, most require bright lights and are unsuitable for a majority of the amphibians covered here.
More Underwater Plants
Two great low-light plants that thrive with aquatic amphibians under a variety of conditions are Java moss (Vesicularia dubyana) and Java fern. Both are varieties of epiphytes (plants that grow on other plants) and flourish if attached to wood or porous rock with fishing line or black thread. They make outstanding background or middle-ground plants. To remain looking its best, Java fern requires regular removal of old sections and replanting with new growth because the leaves have a limited lifespan. Because it is fast growing, Java moss needs to be harvested on a regular basis to prevent it from invading the entire habitat. The African water fern (Bolbitis heudeloti) is another underwater fern that is readily available and sports attractive cut leaves. It also grows best when attached to wood in the tank.
The aquatic section of this floating frog setup shows various aquatic plants. This enclosure would also be ideal for various newts.
Filtration
To filter shallow water, use a sponge (foam) filter that is powered by an air pump, readily available in most specialized aquarium and reptile stores. Plastic foam filters perform consistently well in both small and large tanks. My personal favorites of the commercial products are the Tetra Billi sponge filters. These units are powered by air pumps, with the plastic sponge acting as a mechanical filter (trapping fine particulate matter in its cells) and as a biological filter (with the bacteria colonizing the cell spaces and breaking down ammonia and nitrites). Generally, you should provide filtration with at least an air-powered sponge filter whenever water is deep enough (3 inches minimum if you cut down the outlet tube).
Foam filters are my first choice for large tanks (I use large custom units equipped with power heads), but I also recommend an external power filter that combines mechanical (foam pad), chemical (activated carbon), and biological (e.g., biowheels) filtration. These filters prove particularly useful for tanks containing large amphibians that eat large amounts and quickly foul their water, such as axolotls and African clawed frogs. If using a sponge filter, cut back the outlet using a fine saw so it is just below the water surface.
Air pump-driven sponge filters are inexpensive and very effective filters for water sections of gravel bed vivaria. Remove the sponge filter every one to two weeks and squeeze the waste into a bucket of water. Do not try to thoroughly clean or rinse the sponge filter because its effectiveness comes from the bacteria colonizing the foam cells. In deeper shoreline tanks with at least 2.5 inches of water, you can use thin motor-driven submersible filters.
This sponge filter has an outlet stem cut to accommodate the shallow depth of a shoreline vivarium. Sponge filters are powered by aquarium air pumps and are ideal for shoreline vivaria and smaller aquaria.
In larger setups, use a miniature water pump with the outflow tube pouring over the gravel layer, which serves as a biological filter bed. Because water pumps generate heat, they are not recommended in small setups due to the risk of overheating the water.
Biological Filtration
Biological filtration is a process whereby biological organisms remove or neutralize waste matter, pollutants, or toxins from a liquid, usually water. In closed systems, such as aquaria and vivariums, the process usually refers to filtration by nitrifying bacteria, which break down ammonia (NH3) from animal waste into nitrite (NO2) and then nitrite into nitrate (NO3). Nitrate is less toxic to animals than ammonia or nitrite but can still accumulate to toxic levels unless water is changed on a regular basis. Most aquarium biological filters aim to provide high surface areas on which these nitrifying bacteria can attach and form biofilms. Plants can also play a role in biological filtration by providing surface areas and utilizing ammonia as a nutrient.
Miniature submersible power filters can be very effective in shoreline vivaria and smaller aquaria. This small unit has effectively filtered the water section in a 4- by 2-foot shoreline setup for three years.
