Hi
I'm relatively new to fish keeping. I have a 40l tank with 6 danios in.
Just recently got a 180l tank which I intend to plant up this week and let cycle.
I thought I wanted a betta, guppies, some tetras and a bristlednose plec. However after more research I think I should re think the betta. The danios I'd move to the bigger tank also once it's cycled.
My question is which tetras will he best suited? I initially wanted neons but worry they're too small.
I also read on a different thread that pearl gouramis might be a good fit but I'm worried about over stocking AND worrying that I won't have enough fish in shoals for them to be happy

Hi

As you have danios already you'll need to build around them, so first increase their shoal to 10-12. You could have neons with them as they will cope with the cooler temperature danios prefer, or as a slightly larger alternative have a look at harlequin rasboras. In a decent shoal, they're a very attractive species (IMO). Pearl gouramis would also be OK in with danios and harlequins, either a pair or trio (1 male, 2 female). A bristlenose pleco will also be fine, or a group of peppered cories might take your fancy as bottom dwellers.

Thanks for that, I did get my eye on the harlequins but tbh I want everything
What about guppies?

Guppies are hard water where the others you've mentioned like it softer. They're also very badly inbred and don't really last long and tend to be sickly.