tropical aquarium

Question
Hi,
I'm going to set up a new aquarium in a couple of weeks and I need some advice. I'm in Melbourne Aus. So setting up a tropical tank in winter is challenging. I have previous experience with mostly cold water fishes (and some tropics in tropical country). I have two healthy fantails in a 15 letre tank now. Capable of keeping a healthy aquarium. I've researched as well. I haven't got any equipment yet. Planning for a fair tank maybe about 50x40x40 cm. This what I'm planning on getting, so advice me on any inappropriate choices.   

TYPES of fishes :angel fish, guramis, platies, guppies, sward tails, alge eater. can they be together? How many? who else? (maybe neon tetras and tiger barbs later)  

Heating: 22/23 C maybe. How many watts? Filter: undergravel. How big?

Plants: what plants? live or plastic(if live easy to grow?) do plants have temperature needs as well. (Because I can get some (well treated) from the nearest creek-cold water)

Lighting:how many watts?

Gravel: black  

areation : under gravel filter(air lift) is it necessory to leave the filter on all the time or can i turn it off at night?(energy efficiency)

Food:tropical dry flakes. Do not prefer live food.   

Eventhough the tank is bought in 2 weeks, will leave for some weeks to settle ammonia.    Thats all for now.  hope its enough detail.
thanks km.

Answer
The tank your deciding sounds large enough however I am unsure as I am used to gallons. Your fantail tank is 4 gallons. This is what you can place in the tank.

Fish:
Top dwelling:Angelfish 1-2(can be semi aggressive)
Mid dwelling:groumis(1-2(depends on what kind))platies 1-2 guppies 1-4 sword tails 1-3 neon tetras(1-2)
Bottom dwelling:algae eater(please note they can get VERY large so I suggest only 1 and look into investing into a larger tank when it gets older)
I do not suggest tiger barbs as they can be very aggressive and terrorize your other fish.  I suggest only 15 fish per every 15 gallons with an equal of depth levels. Which means 5 for top max, 5 for mid max, and 5 for bottom max. The choice is yours however.

22/23 C is a good temperature and would work fine.
The wattage is up to you, I use a flourecent light that works very well so just get a hood light that fits well and you should be fine.

I don't recommend a undergravel filter as it will not collect the waste fast enough. I suggest looking into a filter that takes waste and collects it. I use a bio wheel penguin made by marineland I believe. And  just look at the filters recommended tank usage to find out how big you'll need.

I like live plants but plastic works just as well. Some are easy to grow others are not, if you want a hardy easy grown aquatic plant I suggest Java moss and Java fern. Yes plants do have temperature needs and they are usually around the same temp as the fishes. If they are cold water plants I do not know how well they would take to your tank but you can try. Make sure you introduce them slowly just like you would with fish(take a plastic bag use the water you got from the creek and slowly after a period of 1 hour add your tank water to the bag, feel both bag and tank water and when the bag is just the same as the tanks water you can add the plants to the tank.) make sure you do treat the plants though.

Lighting is up to you. Look above for lighting.

The under gravel filter would work fine with aireation. You should leave the tank on all the time as waste builds up and the filter can not keep up with it if it is not on also the beneficial bacteria would die.

Fish flakes should work fine with your fish unless they are very picky eaters and if thats the case you'll have to invest in live foods,(worms do just fine(cut them up first however before giving to fish))

To help aid in the balance of your tank you can add some ph balance and other chemicals to help it out, just go to a fish store and ask from starting tank chemicals. You can however just let it settle which is more time however less expensive. Thanks for asking me. Have a nice day!