Hi and welcome to the forum
You should contact your water supply company via their website and look for a water analysis report. Post a copy here or just go through it yourself and see what sort of nasty stuff is in it. You can also check the pH, GH
(general Hardness) and KH
(carbonate hardness) of your water on that report. Depending on what the pH, GH
are will determine what fish you should keep.
Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH
below 150ppm) and a pH below 7.0. Angelfish and discus get too big for your tank, but most of the other fishes have small varieties that should be fine in a 29G tank.
Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH
around 200-250ppm and a pH above 7.0.
If you have very hard water (GH
above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH
and keep fishes from softer water.
A word of caution on dwarf gouramis (Colisa lalius) and all their colour varieties. They are regularly infected with the Gourami Iridovirus and or Fish Tuberculosis (Fish TB). There is no cure for either disease and once they are in your tank, they will be there until you scrap the tank and disinfect everything. People should avoid the dwarf gourami (Colisa lalius) until the Asian fish farmers clean up their mess. There are a number of other smaller species of gourami that are less likely to have these diseases and they are much better choices.