Before adding new frogs to an enclosure, it is best to quarantine them for 30 to 60 days.

If you put a new animal directly into a fancy terrarium that you have spent hours designing and the animal dies, you will have to tear the whole thing apart, disinfect the entire thing, and you even have to discard the live plants, soil, and any decorations that can't be sterilized. It's a waste of a lot of time and money, not to mention frustration.

These days, the chytrid fungus is a real danger, even in captive populations, plus frogs can die from other causes, sometimes as simple as stress from shipping. If one of your new animals does die from something like getting knocked around during shipping, unless you get a necropsy, you won't know for sure that the cause was not a disease of some kind. Even necropsy information will sometimes be uncertain, so you almost always want to default to the practice of completely eliminating any chance of contamination of your other animals.

For this project, I used:

10 gallon aquarium (I got this one from the goodwill store)
Off-the-shelf, heavy duty screen lid
Glass panel for top of screen lid (from ReSource)
Repti-heat cable (14.75 ft size)
Felt, stick-on pads
Electrical tape
Industrial scissors (for cutting screen)
Razorblade scraper (for cleaning glass)
Driveway gravel
Piece of window screen (from ReSource)
Shredded red cedar mulch (from Lowes)
Bed-a-beast, compressed coconut husk bedding
ExoTerra forest moss, compressed sphagnum moss bedding
Zoo Med floating turtle log (I got mine from the goodwill store)
Split pods from Josh's Frogs
Pothos cutting (from one of my houseplants)
Organic potting soil (no chemicals or perlite)
Rock-shaped water dish (I got mine from the goodwill store)
Lees mealworm dish
Low wattage light fixture (recycled from an old aquarium)
Compact fluorescent bulb in daylight spectrum

If you use recycled items or items from the goodwill, like me, it's a good idea to clean them thoroughly and disinfect them, then let them sit in sunlight for several hours before you even bring them into the house.

Step 1: Apply Heat Source

Tape the heat source onto the bottom of the tank, allowing for a temperature gradient. I wrapped the extra portion of the heated cable around and onto the side of the aquarium, as you can see in the photos. (The cable has a portion near the plug end that is not heated, so that part of the cord between the tank and the outlet won't get hot or waste energy.)

Cut the felt pads into thirds and use them to raise the tank slightly, so the heat doesn't build up too much and to allow the heat cable to pass under the edge without getting damaged.

You could use one or two small undertank heating pads, but do use the felt pads, no matter which heat undertank heat source you use.

Step 2: Add Water Reservoire Substrate

Fill the bottom two or three inches of the tank with large bits of something that is water-resistant. I used driveway gravel.

Step 3: Put Screen Over the Substrate

Cut out a piece of screen so it is larger than the tank.
Cut slits at the corners, as shown in the photo.
Fold two of the sides in, as shown. (Check the size to make sure the screen will fit.)
Turn in the corners, as shown.
Tuck the extra piece with the raw edges under, as shown.
Fold the final edges in. (Check the size to make sure the screen will fit.)

I always fold the edges under and hide all of the raw edges, in order to make absolutely sure that if an animal comes into contact with it, they will not be injured.

If you are making a false bottom using this method, and it is going to be in use for the long-term, it would be better to use a nylon screen, rather than the metal screen that I recycled for this project. Exposure to water will eventually damage the metal screen that I used, but this is a quarantine tank, which will only be in use for a couple of months, so it will be fine for this purpose.

Step 4: Layer Soils and Mosses

Put in a mulch-type layer on top of the screen.
Add coco fiber on top of the mulch.
Put the moss on top.

Step 5: Add Hiding Places and Live Plants

Match the size and type of hiding places and plants to the animals you will be housing.

Some general rules of thumb:

Make sure that whatever water dish you choose, the animals can get out of it easily. Place the water bowl so you can remove it, clean it, and refill it easily and quickly.

Jam moss into any crevices where you think an animal might crawl and get injured.

This particular quarantine tank is for Dendrobates azureus (Blue Poison Arrow Frogs), which only grow to be 2 inches long at the very most. In the wild, they live in crevices and caves near running water.

For a cave, I found a turtle log at the local goodwill, which is hollow and has cavelike holes. It's big compared to the frogs, but it is sterilizable and with some moss inside, it's pretty great. I also like that it is easy to see inside of it, so I can find my frogs easily, since they are in quarantine and I am checking their health and activity levels several times per day.

I also got some split pods from Josh's Frogs that are the perfect size for Dendrobatid frogs. They are cheap and organic, so I don't mind using them once, if I have quarantine deaths. (If I somehow ended up with a frog infected with Chytrid fungus, I could burn the pods or soak them in bleach and then compost them. I would NOT put items from an infected tank into the compost heap or into the trash without first making sure that they would not spread Chytrid into the environment.)

I added a cutting of pothos in a very small pot, so the frogs have some living plants in their environment.

Step 6: Make Sure the Lid Is Escape Proof

I added layers of tape to the corners of the store-bought lid, to make absolutely sure that even the tiniest 1/4 inch froglet could not escape and to eliminate the temptation from larger froglets to try to wedge themselves into the crack and injure themselves.

Make sure that there is no sticky surface exposed on the inside.

(I am also a big believer in spring clips, which I will be installing on this lid, as soon as I can get some JB weld.)

You can certainly use a glass or plastic lid, but if you have cats, like I do, screen lids with clips are the best alternative.

Step 7: Final Touches - Retain the Moisture and Add Muted Lighting

I found a piece of glass at ReSource, which is just the right size to cover 95% of the screen lid. A glass or plastic cover will help retain moisture and keep the humidity levels high in the tank. Where I live, in the high mountains of Colorado, the relative humidity is only 40% on a good day, so this is especially important to my frogs.

For lighting of some amphibians that live under thick foliage (like the Dendrobates azureus) it is best to have dim or filtered light. This poses a bit of a problem because you want the plants to stay alive, but you don't want to expose the animals to scorchingly bright light. My solution is to use a low-wattage bulb with a daylight spectrum. Note that some other amphibians live in brightly lit habitats and they have different lighting requirements.

I used an old 40 watt light fixture from a small aquarium, and put in a compact fluorescent bulb, for the daylight spectrum without too much heat.

Certainly, there are ways to modify most of the steps in this instructable. As long as you are mindful of the physiological needs of your animals, you'll do OK. The beauty of a quarantine tank is that it is small and easy to modify if you decide that you don't like it or the animals need a change.

Good luck with your critters!