20l vs. 29 vs. 40 g for beginner

Hi,

I posted before. The background is that I was gifted a 20 g high with filter (used) and can't set up the tank until sometime in September when we are back from vacation. I read about the nitrogen cycle.
Having too much time to inform myself, I realized that I really don't like the size of the tank and consider getting a larger one. But which one?
Also, the more I read about fish, the more I can't make up my mind. I would prefer fishes from one region and wouldn't really like to Asian and South American fishes in one tank.

I like peaceful fish, preferably not wild caught. I would like not too many different fishes together, rather larger schools and if possible no fry. Maybe 3 or 4 species, I could go with less, too.

Here is an idea of what I like so far (visiting all kind of fish stores and staring at the fish forever )

- love cichilds but due to their territorial nature I think I need to go with a South American species, Bolivian Ram sounds good to me
- bristlenose pleco
-cory cats
- ember tetras
- Norman's Lampeyes - Gouramis (pearl, licorice, chocolate, maybe honey)

The substrate will be black sand, live plants. I already bought driftwood

I am open to other fishes. We have city water that is soft, I am trying to find out the hardness which hopefully will happen tomorrow.
Looking forward to hearing from you

Thanks!

 

Bigger is always better! You could always have multiple tanks.

 

That's right, in my head I am planning 3 already. Shell dwellers, Betta and this one

 

Lol same here. I started with a 30G and now I have a 30 a 10 and soon to be a 55

 

It honestly depends. I know a lot of people will tell you to always get a large tank. I am currently setting up a 40 gallon breeder for a peaceful community, but I don't always want a community nor a schooling fish.

I love bettas, shrimps and snails too. I have a lovely ten gallon with a betta and snails in it. I'm also thinking about getting a smaller tank for a shrimp colony for my home desk.