Join Date: Oct 2010
Location: Victoria, Australia
If you have soft water, I would look at killies. Basically the same personality as bettas (although they generally do best and live longer in cooler water) and they are extremely beautiful.
A pair of something like Aphyosemion australe or Aphyosemion striatum would do perfect in a 5 gallon NPT. If there are enough plants, I would expect you would also see some fry surviving.
Neither of these are annual killifish, so they have a lifespan of around three or so years I believe. They are also both good for those new to killifish as some of the species can be sensitive.