“I have been reading the care sheet for poison dart frogs (i think i’m going to go with them), and there are two things i’m uncertain about.
What type of heating do you recommend? Should I use overhead lighting, lights attached to the wall of the terrarium, or something else? I am going to be using a submersible heater in the water section, if that matters.
My other question is the humidity. I am considering buying (or making) a mist machine or fog machine. Should I be striving for thin mist, or rain-like mist? Does the fact that I will be having a waterfall/river factor in?
The first thing to do before adding heat is to check the temperature in the terrarium. Use a good quality thermometer, not just one that sticks on the glass. I like the digital ones with an external probe best.
Depending on the room the terrarium is kept in, heating may not be necessary. If the temperature during the day in the terrarium regularly reaches the low to mid 70’s and drops at night are not falling below the mid 60’s then no heating is needed.
If you find, though, that it is too cold there are a number of ways to heat the enclosure.
As you suggest, you can use a fully submersible aquarium heater underneath a false bottom or elsewhere in water. Many hobbyists prefer this method because you can set the temperature and the heater will go on and off as needed. Additionally, water has a high specific heat and so it will take a long time to cool down; it’s efficient.
The downside is that a submersible aquarium heater in the water underneath a false bottom is difficult to access, so if it breaks or you need to adjust the temperature you will have to get creative.
Another easy option is to add a reptile heating pad to the side of the tank. If positioned below on the bottom as designed, you will barely notice a difference in temperature if using a deep substrate, so instead I have used heating pads on the side or back of enclosures with success. Usually you will want to also incorporate a background, such as cork bark, to buffer the temperature so that the frogs cannot access hot glass directly.
Lastly, you can use a heat lamp or ceramic heat emitter above the terrarium, but these have a tendency to dry out enclosures, which you definitely don’t want when keeping poison dart frogs.
You may also find using a combination of these different heating devices is best. For example, perhaps for most of the year you use an aquarium heater underneath a false bottom but then in the winter you also add a heating pad.
The most important thing is to monitor the temperature with an accurate thermometer and check it daily. Do this before buying or adding any heating components, and keep an eye on the temperature throughout the year as the temperature in the house changes.