Hi Dahly

Here are some of my calculations for your fish. As you know, the general rule is to have 1 inch of fish per 1 gallon of water. But it's even better to have 1 inch of fish per 2 gallons of water (better for the fish, that is - because in natural environment there are not as many fish per, for example, 30 gallons of water as there are in aquaria).
From what I read, Corys that you have grow up to 2 inches, clown pleco up to 5 inches, dwarf gouramis up to 2 inches, white skirt tetras up to 2 inches, and diamond tetras up to 2.5 inches. So:
5 white skirt tetras x 2" = 10"
7 diamond tetras x 2.5" = 17.5"
2 corys x 2" = 4"
1 clown pleco x 5" = 5"
2 gouramis x 2" = 4"
The total is
40.5 inches. Your tank is
29 gallons in volume. I think you shouldn't be getting any more fish! Unless I got wrong the sizes of your fish once they're adult. If so, disregard this calculation.