I was wanting to get a mercury vapor light for a bearded dragon. I know that they produce both heat and uvb. Other than a heat lamp at night, is there any other kind of light I will need for my tank?
That should be the only required light, however most people end up needing a secondary heat source to get the correct temperature gradient. It also helps to lighten up the tank. You can use standard incandescent bulbs for this, nothing fancy is necessary. Alternatively, you canbuy a ceramic heat emitter and use that at night as well as the secondary heat source during the day. They are a little more expensive but they last a very long time and do not produce light which is ideal for nighttime heating.
Jess got you on lockdown for temperature needs - On the other end of the spectrum, If you find that the temperatures are alright; you may end up also needing to incorporate a standard flourescent bulb to add extra light to the enclosure depending on the species and size of the viv. You'll have to look at it sideways, sorry LOL! Here I am using an MVB as the primary heat and UV source for a Bearded Dragon; temperatures are ideal and the bulb is close enough to ideal levels of UVB. But, in this larger enclosure (4' x 2' x 1.5' lwh) the single bulb doesn't really cut it for lighting the entire thing up. I opted to buy a cheap flourescent fixture and standard flo bulb to accomplish more light in the viv for my beardie. The only reason I'm suggesting a Flourescent bulb is they are more cost effective for lighting; they light up greater areas with less wattage and produce little to no heat. These are best if your temps are spot on and just need to light things up. Standard household incandescent bulbs produce light and heat (as Jess mentioned) and are good if you need to bump temps up just a bit while adding more light as well. Here's a good resource for MVB's and UVB producing bulbs if you haven't seen it yet = ) http://www.reptileboards.com/threads/uvb-basics.64396/
So if I don't have enough light with an mvb use a fluorescent light along with it. Got it. lol I had another question about ceramic bulbs for night time use. Can those be used by any fixture or does it have to be specific? I've been looking at fixtures online and haven't found any that say "yes, you can use with a ceramic bulb."
Any fixture will work for them = ) erm, any fixture that can accomodate a typical household bulb like your average incandescents or compact flo's will also house the CHE just fine. You really only need to use CHE's (Ceramic Heat Emitters) if temps dip quite low... as long as temps can warm back up again its usually not a problem to allow for nighttime dips. You don't need temps to be the same at night as they are during the day. For example, its generally accepted that as long as temps don't get below 65 degrees F for a bearded dragon, no supplemental heat is needed during the night.
The only other thing you might want to keep in mind when buying fixtures is to make sure that the maximum wattage for the fixture is larger than the wattage of the bulb. For example, if you buy a 100 watt light, you will need a fixture that can handle a 100 watt or higher bulb (although I would go a little higher just to be safe). This probably sounds obvious, but sometimes it's the little technical details that can be overlooked. I would also try to get a fixture with a metal or ceramic base. They tend to be much more durable. The cheaper plastic ones would work fine for a standard household bulb, but for a basking heat lamp they get a little too hot for comfort. And they break pretty easily, so it's just not worth the money.
