I have found that bettas are the "gateway drug" so to speak (They Might Be Giants fan) ...then its NPTs, corie cat fish (my emeralds are breeding out of control...on F3 generation...every time I do a water change (about 2x every 6wks, they get a partial since its a newer NPT)...they spawn! And let's not forget the gouramis,and my shoal of rainbows....and it all began with 1 2.5g and 1 betta! LOL!
Now, I am researching a vivarian for poison dart frogs...which I only found out about because it seems over half of your freshwater shrimp breeders also do dart frogs and they are gorgeous!
....did I forget to list the shrimp? Tangerines tigers, blue velvets, and RCS....which all need their own NPTs since if they're housed with fish, they tend to feel a bit hunted (go figure) and will lose color and hide...the ones that don't, get eaten...
Did you guys know that all of this can be found on Aquabid, except the dart frogs, of course! :)