This is a discussion on help please, im new within the Freshwater and Tropical Fish forums, part of the Freshwater Fish and Aquariums category; -->
yes i would say to get a heater,there are many on the market,
not sure if there are any reccomendations in the equipment ...
A couple of other options for a 10 liter tank:
-1 dwarf puffer (cool little guys, but they need live and frozen foods so be prepared for that)
-1 badis badis (dwarf chameleon fish - harder to find but very cool. Also needs frozen and live foods)
-1 sparkling gourami
-1 male and 2 female Endler's livebearers (like smaller versions of guppies. The males are gorgeous. Be prepared to sell some babies back to the fish store)
You definitely want to get the tank cycled before you add any sort of creature to it. I strongly recommend researching the aquarium cycle and purchasing a good liquid test kit like the API Freshwater Master Test Kit (cheaper online than in stores by a longshot).