Actually there is a place on here where you can create your tank
Click on fish profiles in the menu at the top of the page, then click on any fish. Down at the bottom of the profile you will find the community creator; just enter your tank size and filter type, click 'save' then enter the fish you want by selecting them from the profiles.
You can save your virtual tank but you have to register separately from the forum to do this.
As for the fish you currently have:
golden barbs - temp 16 - 24
oC, pH 6.0 to 8.0, hardness 36 - 357ppm (2 - 20 German deg)
mollies - temp 21 - 26C, pH 7.0 - 8.5, hardness 270 - 625ppm (15 to 35 Ge5man deg)
dwarf gouramis - temp 22 - 27C, pH 6.0 - 7.5, hardness 36 - 320ppm (2 - 18 deg)
pearl gouramis - temp 24 - 30C, pH 5.5 - 8.0, hardness 36 - 535ppm (2 - 30 deg)
As for the plec, you don't say what species it is, though I assume it is a bristlenose as they come in an albino form.
bristlenose - temp 21 - 26C, pH 5.5 - 7.5, hardness 18 - 268ppm (1 - 15 deg)
All that means is that apart from the mollies, the fish you have are fine in slightly soft acid water to slightly hard alkaline water. Mollies are the exception as they must have hard water to do well. If kept in soft water they become prone to disease. Endlers too like hard water though they will cope with softish water better than mollies.
The main problem with endlers is that they are small; males certainly are. And the pearl gouramis and mollies might be too big for them. They might well try to eat small fish, and even if they don't they could well stress the small fish.
Are there any other fish bigger than endlers that you like instead?