Well the best to do (apart from coming here and asking first & then shop):
- Exactly where you wanna set up the tank at, measure it what size you have available there
- Quiet filter is not a problem, and for small tank I suggest a sponge filter
- Do you want the tank planted (that determines what lights to get for the tank)?
- Decide first what fish you like, many are tropical, you say 'cold water' which means I assume you don't want to add a heater but rather house them at room temp, that narrows it down quite some (Brows here, see what fish looks nice to you https://www.liveaquaria.com/product/...lies.cfm?c=830
- Last but not least, you need to know your water parameters as many fish require a differed hardness (KH) and a different pH. Meaning if you get fish that require soft water, houseing them in hard water will not allow them to thrive and possibly die quick and vise versa.