I'd think ahead a bit if I were you. Do you want to breed them? I got Black Mollies and they bred very well and most were eaten by other fish as the Mollies aren't what you'd call good parents and just let the fry go their own way. Some did make it through and I managed to sell these to the LFS. My next hatching was of my Kribs. Beautiful fish and when the eggs hatch there's a cloud of fry all being followed and closely guarded by the parents. They chase every other fish well out of the vicinity of the fry. I caught them all and put them in a separate tank all by themselves as there were around 50 - 60 of them and I didn't have room to have them all grow up in the tank they hatched in, and of course the other inhabitants were stressed out being chased all the time.
The problem is that as soon as the hatchlings were taken out and the parents stopped looking sorry for themselves they were at it again. Another hatch occurred within 3 weeks. The only thing I could do was take the parents out of the tank for a while and give the other fish a fry-up (sic). They had all been eaten in less than 5 minutes. The others are still in a separate tank but they grow so slowly that I can't sell them on yet. It's been almost 7 months.
So breeding might be ambition but think it through.
Another trap I fell into was buying pairs of fish, ie a male and female as could be best ascertained. These were generally larger fish such as the Mollies, the Kribs, Firemouths, Pearl Gouramis etc. While they are all really nice to look at there have been too many battles and even lost fish. Being much the same sort of size they are very territorial and especially the Kribs. They also don't have the same activity level of smaller fish that like to be in a group of 8 for instance. The Kribs hide in their tunnel unless they come out looking for a fight or food, the Firemouths hide behind a large lump of bogwood but do get about a bit but when they do they have a go at the Pearl Gourami and the Kribs if either of them are swimming free at that time. I even saw the male Firemouth caught in an ambush yesterday. He was holding his own head to head with the male Krib in a fully flared red throat standoff while the female Krib swam round the back and nipped his rear end.
My post tells you what I'm doing about it.
I am well satisfied with having smaller fish in groups that are active and less trouble with the other inhabitants. It's good that there are so many Tetras that like soft water so I'd start there. There are loads of them that aren't readily found on a simple search for Tetra in Google.