I may have missed it but what are your water parameters? (pH, GH, KH).
The danger of impulse buying (i.e. taking your wife and daughter along) is you may end up with fish not ideally suited to your water.
FWIW 180 liters is a nice size for a community. I started mine thinking I'd like a variety, but have ended up reducing the number of species and going for bigger groups. I actually dropped the idea of a "centrepiece" because IMO 30 tetras shoaling together makes a far nicer display than any single (more expensive) fish as a certrepice.
I did check on my phone in the shop that they would suit my water parameters -
PH 6.8
Unfortunately the test kit I have doesn't have anything for GH / KH but according to the water provider report for my area the water is very soft - hardness Clarke 1.47.
Didn't intend to take the fam but it was one of those days, rainy, toddler going stir crazy, mrs looking like she was contemplating hard liquor and a tub of sleeping tablets, it was necessary
Agree about the number of species, at first I was all about getting as many different species as possible, now I'm starting to think less is more. Although I wouldn't mind something relatively big (for the tank size) and brightly coloured that stand out a little more. Possibly something that does well in a pair.
Must admit, the whole thing hasn't gone to plan since I began. I had all these ideas of grand aquascaping and really specific fish choices, and since day 1 I've not been happy with the way I scaped it, and now my first fish were not even really in my plans until I went to the LFS yesterday, despite the shortlist I have been keeping on my phone! Well, I always wanted the Oto's actually but not the Harlequins.
That said, I enjoyed the Harlequins yesterday, they seem to like swimming up to the filter outlet and riding the current back to the other side of the tank. Fun to watch!
How long should I leave it before adding some more stock? I was thinking this weekend, all being well in the tank.