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CHAPTER 3

HOUSING

Enclosures

The best enclosures for keeping amphibians are all-glass tanks with sliding screen tops or aquaria with screen tops. Open-top aquaria work for some aquatic species, such as dwarf underwater frogs and axolotls, as long as the water level remains at least a couple of inches below the top of the tank. Floating frogs can be housed safely with dwarf clawed frogs in half-filled tanks.

The plastic terrariums commonly recommended for keeping frogs and newts can be used as temporary housing and for quarantining smaller amphibians, but they are unsuitable as display enclosures. Plastic terrariums become easily scratched and unsanitary, and they have no visual appeal. When keeping frogs and newts, the saying “glass has class”holds true.

This display by Reptile Haven (Oceanside, CA) won first prize in the aquatic division at the 2000 IRBA Vivarium show in San Diego. It housed several paddle-tailed newts. The background was a polyurethane Foam Home unit. In the center, a weighted cork round was planted with cryptocorynes. Java fern and anubias were anchored to the foam background. A powerhead in the foam unit acted as a filter and current generator.

If you have limited space, such as a desktop, start with a tank as small as 2 gallons for tiny species such as dwarf clawed frogs, floating frogs, or Oriental fire-bellied newts. For the other species covered in this book, you’ll need at least a 10-gallon tank, though larger tanks—20 gallons or more—are preferred. In larger tanks, the quality of water and substrate (bottom material) remains more stable and requires less maintenance. The animals also utilize the extra space.

The importance of screen tops for most amphibians cannot be emphasized enough. Thousands of captive frogs and newts end up as mummified dust balls because their owners failed to provide an aquarium cover. Most newts, salamanders, toads, and frogs can escape an uncovered tank—and once they do, they will not survive.

Shallow Shoreline Vivarium

For semiaquatic species, such as Oriental fire-bellied toads and newts, gravel bed shoreline vivaria might be the easiest setups to design and maintain. As the name indicates, this type of vivarium includes a substrate of gravel that simulates the shoreline of a stream or pond, combining equal areas of shallow water and land. To create this kind of setup, first pour a 1- to 2 ½-inch layer of a washed ¼- to ½-inch diameter aquarium gravel or fired clay substrate used for growing aquatic plants. The next step is to shift part of the substrate to one side and create a depression. This area will become the water section. For most species, this depression should cover ⅓ to ½ of the floor surface, depending on the habits of the animals you plan to introduce (less for primarily ground-dwelling species, more for primarily aquatic ones). The depression should be 3 to 4 inches deep. Landscape the land/gravel area with rocks, wood, and plants. Add small sections of wood and smooth pebbles along the water’s edges to give the vivarium character and to hold the gravel in place. Leave open areas for easy access to and from the land area.

Select plants that grow well hydroponically (in water), such as Chinese evergreen (Aglaonema sp.), pothos, arrow-head plants (Sagittaria spp.), and variegated Wandering Jew (Zebrina pendula). These can be planted in the gravel land sections. Simply remove plants from their pots, wash their roots free of soil, and insert them into the gravel layer. Then add cork bark sections to the land area to provide shelters and dry platforms. Cover the exposed gravel on the land with moistened green moss. Add water to the gravel depression, to a level about two-thirds the height of the land section.

One or two bulbs in a fluorescent fixture running the length of the tank provide the necessary light. For species that like to bask, such as fire-bellied toads or leopard frogs, place an additional low-wattage bulb in a small reflector-type fixture over a basking site, such as sections of wood, rock, or an open gravel area.

This shallow shoreline vivarium was designed to include treefrogs and anoles.

Gravel bed vivaria are easy to set up and can be very decorative. In this setup, round pebbles line the edge of the water section.

Weekly Water Changes

The water in a shoreline vivarium should be changed weekly. In small setups, use a turkey baster to remove the water. With deeper water, use a siphon or, even better, a manual sump pump. Before siphoning or pumping old water, pour additional water over the land area to lightly flush the gravel surface and to drive waste into the water section. When replacing the water, pour new water into the water section, not the land area, so that it is relatively clean and free of debris.

The water in this shoreline tank is being drained with a manual boat bilge pump. You can also use siphons and industrial vacuum cleaners for this purpose. Whatever you do, never start a siphon using your mouth.

Flushing

At least once a month, flush the gravel bed more thoroughly. To do this, pour greater amounts of water over the land area and siphon out the flushed water from the water section. Two to three flushes will clear out a significant amount of waste while retaining enough bacterial colonization in the gravel to still act as a biological filter.

This is a basic inexpensive shoreline setup. The land area is a gravel bed. The plants are Chinese evergreen rinsed free of soil and planted in the gravel. A layer of moist moss covers most of the land area. A section of cork serves as a shelter. A low-wattage incandescent bulb over a basking site or a fluorescent bulb is used for lighting. The water can be changed using a small plastic container or a turkey baster.

Advanced Shoreline Vivaria

You can create a larger, more complex shoreline vivaria (at least 6 square feet) by planting a variety of shoreline plants and increasing the lighting over parts of the water section.

Along the shoreline, add Java moss (Vesicularia dubyana) into the water. With time, the moss will creep partially onto wood, cork, and rough rock while spreading in the water section. Also place semiaquatic plants, such as dwarf umbrella (Cyperus alternifolius dwarf), sweet flag (Acorus gramineus), slender arrowhead (Sagittaria graminea), Anubias spp., sword plants (Echinodorus spp.), and pennywort (Hydrocotyle spp.), along the shoreline with their bases submerged. Always leave open passages that allow frogs to easily access and exit the water. To create even more biological complexity, you can grow aquatic plants in the water section. To do this, add a layer of substrate (e.g., gravel, sand, or clay) to the floor of the water area, and plant with short aquatic plants such as dwarf Sagittaria (S. subulata var. dwarf).

Aquaria

Hypothetically, aquaria for aquatic amphibians should be set up in the same manner as aquaria for fish. However, unless you want to keep very large species of fish or amphibians, there is only one way to design aquaria: create a natural-looking biological system using biological filtration and live plants to maintain water quality. Step-by-step details for this technique are provided here:

Step 1. Choose tank size and animal density

Because amphibians vary in proportion, it is difficult to provide specific guidelines based on size. A very general guideline is that the tank should have a length at least four times the length of the largest animal. For example, a 3-inch-long newt needs a tank at least 12 inches long. A general guideline for animal population is to provide a minimum of 1 gallon of tank space for every 2 inches of animal. Generally, a lower density of animals reduces biological waste, which makes water quality easier to maintain.

Step 2.Add substrate

Prior to introduction, thoroughly rinse the substrate to remove dirt and dust. At the bottom of the tank, place a 1.5- to 2-inch layer of coarse aquarium sand or fine aquarium gravel (up to a 0.5-inch diameter) or a fired clay substrate. Do not use fine silica sand, which is too dense for adequate root penetration, and do not use coarse gravel, which is too thick for good rooting.

Step 3. Furnish with rocks, wood, and cork bark

Next, add landscape structures, such as fresh water drift-wood, rock, or cork bark. Aquarium stores usually carry a good selection of rock and wood suitable for use in tanks, while reptile supply stores usually carry cork bark.

To achieve aesthetic uniformity, select one kind of wood or rock that resembles what is found in nature. Use only wood and rock with smooth edges to reduce the risk of injury to the aquarium inhabitants. The rock and wood should cover less than a third of the surface area of the tank. Usually just a few pieces are adequate as background or as a centerpiece around which plants can be arranged.

Much of the wood sold in aquarium stores leaches tannins when initially introduced into tanks. These tannins turn water the color of tea. It might be necessary to change the water many times over the first weeks or months to reduce the level of leached tannins to a point where the water is relatively clear. An alternative is to soak the wood in a large tub of water for several weeks prior to introduction.

Cork bark should be weighted down, glued to the tank sides with silicone, or wedged between the sides of an aquarium. It also leaches tannins, but only for a relatively short period of time.

Cork bark and drift wood should be soaked in tubs of water prior to use to clear them of dust and debris, and to allow tannins to leach out.

Step 4.Add plants

Plant heavily when you set up a tank rather than gradually adding plants over an extended period of time. This speeds up the time required for the tank to become balanced and biologically active. One advantage of a heavily planted tank is that the plants use excess nutrients in the water, leaving little available for algae growth.

Island Aquaria

Island aquaria consist of a tank that holds at least 10 gallons of water, preferably more, with the water level at least 3 inches below the top of the tank and one or two land areas emerging from the water. Because the structures used to construct islands take up space, larger aquaria are better suited for this type of design. You can use freshwater drift-wood or rock to create the islands or attach panes 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.

A small water pump carries water from the water section over and through the gravel section of this shoreline vivarium. Sponge filters are powered by aquarium air pumps and are ideal for shoreline vivaria and smaller aquaria.

Lighting

For aquarium illumination and plant health, use two fluorescent bulbs running the length of the tank. For species that tolerate higher temperatures, such as floating frogs and clawed frogs, use incandescent lighting. I have had success growing certain aquatic plants (such as Sagittaria spp., Cryptocoryne spp., elodea, Java moss, Java fern, and horn-wort) using a single 20-watt halogen bulb in small 2-gallon tanks housing dwarf underwater frogs and floating frogs.

Heating

Most of the species in this book do well at cool to moderate room temperatures, so additional heating is not required. Some exceptions are floating frogs and clawed frogs, which prefer higher temperatures (in the upper 70s° F).

In setups using incandescent or halogen bulbs, the heat generated by these bulbs is usually enough to maintain desired temperatures. If not, try submersible aquarium heaters with built-in thermostatic controls, available in a range of wattage and sizes. Estimate approximately 5 watts per gallon.

Aging

Everyone working with planted aquaria finds that there is an aging cycle. Initially, problems are common because biological cycles have not yet been established. It takes three to six weeks for conditions to stabilize. This time frame allows nitrifying bacteria to build up to high enough levels that ammonia and nitrites are broken down. It also takes at least six weeks for plants to establish by anchoring into the substrate and increasing root mass and body mass. Once they spread their roots and achieve a certain density, aquatic plants effectively take nutrients from the water, limiting food available for algae.

A ventral view of a floating frog shows the tubercled and intricately textured belly.

After this biological balance sets in, the tank takes a sudden turn. The water suddenly becomes clearer and the algae level starts to drop. A key to balancing a planted aquarium is the number of plants. As an example, I originally had two axolotls, a Hong Kong fire-bellied newt, and various fish in a 29-gallon, sparsely planted tank, and it worked well for two years. I added two axolotls, and in time, the plants, the inner surfaces of the tank, and the substrate became covered with algae. Determined to solve the problem biologically, I removed one axolotl, which led to a slight improvement—slowed growth of algae—but the problem persisted. I doubled the number of plants in the setup. Within a few weeks, the algae cleared and the tank was in equilibrium. The same pattern occurred with my tanks of paddle-tailed newts. I had a chronic problem with algae until I added plants and a couple of American flag fish, a species that is very effective at controlling hair algae.

Maintenance

The secret to a long-term successful aquarium is regular maintenance with a weekly to biweekly water change—probably the single most important procedure. Water changes stabilize the composition of the water, add minerals and trace elements, and remove fecal matter and plant debris from the aquarium floor.

As a general rule, every one to two weeks, siphon and replace 25 to 50 percent of the tank water. During siphoning, make sure to remove the biological waste that accumulates on the tank floor. The standard method for changing water is to remove it using an aquarium siphon and 5-gallon bucket.

Do not start a siphon using your mouth. There is a high risk of bacterial and parasitic infections because you can’t avoid taking in the fouled water from the end of the siphon tube, and you may accidentally swallow it.

Siphons with hand pumps are sold at aquarium stores. Manual boat bilge pumps (which are very effective) and industrial wet-dry vacuum cleaners (being careful not to wet electrical parts or to accidentally suction frogs or newts) are also very effective.

Remember to dechlorinate the replacement water. This means buying a chlorine remover at a store that sells aquarium supplies or allowing water to sit in a container for at least twenty-four hours prior to use. In areas where chloramine (a compound of nitrogen and chlorine) is used to treat your water, a dechloraminator, also available from pet stores, should be added to the water. If you keep larval amphibians, leave replacement water in a bucket or tub for at least twenty-four hours before use to let dissolved gasses to dissipate.

Every one to two weeks, clean out filters and/or replace filter media and scrape algae off the sides using a single-edge razor or an algae-scraping tool. Also remove or prune overgrown or dead plants. Wipe dust off the tank cover and the unplugged fluorescent bulb, and clean stains and dirt off the outside of the tank. You can safely use window cleaner such as Windex on the outside glass.

If properly set up and maintained, planted tanks last for years, possibly more than a decade, without requiring a full disassembly, cleaning, and reassembly. I keep several 1.5-gallon setups, heavily planted and stocked with underwater frogs and floating frogs, that are three years old and look better than ever. My larger axolotl and newt setups are going into their fourth year and look the best they ever have.