Stocking Ideas?!

[TeaCosy7]

So I`d had angelfish for almost two years until a faulty automatic fish feeder proved to be fatal during my three week holiday. So at the moment my tank is empty except four cory cats and a bristlenose pleco. The tank is 120 litres.
Now I would really like a typical community tank. Like, one with tetras and livebearers and the like. I am pretty clued up about the basics of fishkeeping.
Problem is, I have no idea what ​species​ of fish to get. Actually no I do have a few ideas... but I need some inspiration too! I don't want to get this wrong.
There are a few species I was quite interested in...
(I should mention that one of the things I am very clued up about with fishkeeping is the fish themselves. I admit I lack in expertise with the more mathematical aspects..)
-Black Widow Tetras (I`d probably get four or five...)
-Marbled Hatchetfish (and yes I am aware that they jump, and yes I have a secured lid)
-Orange Chromides (I heard them mentioned on one of these forums, googled them, did some `homework` and completely fell in love with them (; )
-Normans Lampeye- stunning fish of course I would get quite a few..
-I`ve been looking at lots of different tetras, some I like include Black Phantom Tetras, Serpae tetras, congo tetras (though I`ve heard Black Widow Tetras don't like fish with long fins, so its either one or the other) Red eye tetras, etc.
That's just to give you some idea... I really don't mind.
so to sum this up (sorry its long) I`m looking for some  stocking ideas for a 20 gal community tank, I`m almost not a beginner, I mentioned a few I liked if that would help, but really I`d just like inspiration. I already have a bristlenose pleco and some corys.
Oh and by the way, I`m new here, so.. hi everyone, and thanks for your help ))

 

[squidneh]

My personal preference in a tank that size would be to have a large school of tetras or a large number of live bearers (though you'd need to be prepared for the fry or get only one sex). There is something amazing/fascinating to me seeing a large school behave much as they would if they were in the wild. I'd also up your cories to at least 6. 
 
Do you know the stats of your water?

 

[Byron]

As mentioned above, knowing your water parameters will help us a lot.  The GH (general hardness) is the most important, and then the pH.  You should be able to track down the website of your municipal water authority if you are on municipal water and find the numbers there, or you can call them.
 
While we're waiting for that, I can make a couple observations on the fish mentioned in post #1.  You mention 120 litres, which is roughly 30 gallons (not sure where the 20g came from) so with this in mind...Black Widow Tetras and Serpae Tetras are both notorious for fin nipping.  A group of 8+ (but preferably closer to 10-12) of either, in your 30g would be it.  So I would forget these, as it will limit things a lot (unless you decide you want a species tank).  The corys would be OK with either, but nothing else.
 
Orange Chromide (Etroplus maculatus) is not going to work in this small a tank, see more here:
http/www.seriouslyfish.com/species/etroplus-maculatus/
 
The only issue with the Congo Tetra is tank size; this is a fish that gets 3-4 inches, and it goes through bouts of very active swimming, so I would not have it in anything less than a 3-foot (60 cm) aquarium.  Your tank might be this long, but if not, I would consider other fish.
 
Depending upon your water parameters, we could find lots of soft water fish (tetras, rasbora, catfish), or if moderately hard water, then livebearers.
 
Byron.

 

[TeaCosy7]

I don't mean to argue but I thought anything over 20 gallons was fine- on
aquariumlife.net
Tankplanner.com
Tropical Fish (book)
The Aquarium (book)
And many other websites (would put links but don't know how) say 20 gallons is the minimum size and on seriouslyfish.com they say 120x60 FOR A GROUP which I was not planning on getting if I was going to get orange chromides (sorry if it sounded that way)
I meant it when I said I researched!

 

[Byron]

I don't mean to argue but I thought anything over 20 gallons was fine- on
aquariumlife.net
Tankplanner.com
Tropical Fish (book)
The Aquarium (book)
And many other websites (would put links but don't know how) say 20 gallons is the minimum size and on seriouslyfish.com they say 120x60 FOR A GROUP which I was not planning on getting if I was going to get orange chromides (sorry if it sounded that way)
I meant it when I said I researched!

 
In the link I posted, under "Behaviour and Compatibility," it recommends a group of 8+ for this species, noting that this is a shoaling species forming hierarchies within the group and with fewer the "weaker fish can become the target of excessive abuse by dominant fish or the group may fail to settle down and behave nervously."
 
I assume that this fish is best in a group, to be "natural."  I would point out that Seriously Fish is a scientific site, highly regarded by hobbyists and ichthyologists.  I've no idea who is behind tankplanner or aquariumlife.  Neither says anything about the behavioural needs of this species, so while one lone fish may work in a 20g, that may not be the best way to keep this species.  I will leave that for the cichlid experts.
 
Which brings me to web sites in general, and something I have written about elsewhere on this forum.  One has to know who is behind the site.  Anyone can set up a web page and suggest some sort of "expert" knowledge, but without knowing who is the source of the data it is not always good to rely on it.
 
Byron.