Okay, so I hope it's not bad to resurrect this or if I should post this somewhere else, but I think I'd like to get some dwarf gourami. I also really like tetras, danios and glass catfish. Thing is I don't know how many I could get before i start to overcrowd. Any advice? Also, assuming i should do some live plants. Any suggestions on some that are easy to manage?
Taking the live plants issue first...what is your tank lighting? Light is the most important aspect of plants, and there are species that do very well in low light, some in moderate light, and then there are those requiring high (bright) light and nutrient supplementation. Knowing the light specs will help pin this down.
Turning to your fish interests. A community aquarium, meaning one that has more than one species of fish, has several factors that need to be looked at when considering suitable species. Obviously the fish's temperament (peaceful, aggressive) is important but there are other equally important factors that many overlook. The water parameters (we already sorted out this is soft water, so that's settled) include temperature, and not all "tropical fish" will be best as the same temperature. Then there is water current (from the filter) which can affect fish, some occurring in streams with more current while others may be more standing water fish. The environment, meaning how you aquascape the tank, using plants, wood, rock, etc., is important. The activity level of the species, as some fish are active swimmers while others may be sedate. Combining opposites usually doesn't work for long, as the fish that is being made to accept what is for its species unnatural will be the loser, succumbing to health issues that it would otherwise be able to fight off.
With that background, combining danios and glass catfish will not work. The danios are active fish, preferring to swim around the tank. Barbs are the same. So these two groups of fish in general do not go well with sedate fish, plus being active they are better in longer rather than shorter tanks. And very generally, active fish tend to prefer slightly cooler water than sedate fish would. Tetras depending upon the species can be quite active (Lemon Tetra and Diamond Tetra come to mind as being quite active fish) or sedate (cardinal, neon, phantom tetras for example).
Dwarf gourami is a bit of a risk these days. This fish is well documented for carrying a virus disease that is not treatable. Unless the actual source of the fish, meaning the breeder who raised them, is known, it is best avoided. The Honey Gourami is a much better small gourami, and like all gourami, this is a sedate fish.
Glass catfish are very sedate and very shy fish that can easily be frightened by other fish to the point of refusing to eat. It requires a small group, minimum six but a couple more would be better, and it will form quite a tight little shoal which further helps to keep it settled. Unlike most catfish, this species lives in the upper water column rather than on or close to the substrate. It is an ambush predator, remaining almost motionless among plants until prey drifts by. This species would be fine in your aquarium if planted, and with your water parameters. Floating plants with their dangling roots, and a very slow water movement from the filter, will also help to keep this fish calm and healthy. If you really like this one, I would suggest selecting the other fish around this species. I would also mention that it is quite sensitive to water parameters, and any changes in parameters or water conditions in general, so a very stable and established aquarium is best. Being scaleless, it is more sensitive to any medications and water treatments too.
Good tankmates for the glass catfish include the medium-sized rasboras, such as the "Harlequin" species,
Trigonostigma heteromorpha (the common Harlequin Rasbora), or even better the slightly smaller species
Trigonostigma espei and
T. hengeli. The latter is my personal favourite, with its shiny copper "axe" pattern. Rasboras tend to be much like tetras in their behaviours, but they are almost always quiet, sedate fish, and very peaceful. And large enough not to be eaten...the glass catfish does attain 3 inches and is a predator, so very small fish are not good choices. A largish group of one of these rasbora would be ideal, say 12-15.
For the substrate level, any of the cory catfish would work. There really is no more peaceful a fish group than the cory cats. A group of 12 or so, all one species, or a mix of two or three species.
All of these are well suited to your water.
Byron.