20 Gallon Setup

Hello, I am planning to add new fish to my 20g long freshwater setup.
So far I have
1x clown pleco
5x flame tetra
4x shrimp
3x cories
1x gold algae eater
3x marbled hatchetfish

I am planning to add
6x lemon tetra
6x royal tetra

Can someone please tell me if I am overstocking or if fish aren’t compatible?

 

Just from looking at it, your tank sounds to be maxed out. You really can’t have more than 1 school of fish in a 20 gallon. There isn’t enough room.
Clown plecos, although stay small, produce a ton of waste. I wouldn’t recommend for a 20 gallon.
The tetras are fine in a 20.
Shrimp are fine but will probably have a hard time populating.
Cories need 4 or more in a shoal.
The “gold algae eater” might be an albino chinese algae eater, can you post a picture of it? If it is, it is not suited for your tank and get very aggressive as they get older.
The marbled hatchetfish are good but need groups of 6 or more.

 

Ok, I will stick with what I have

 

I agree you're best to stick with what you have