There is a search feature at the top of the page, and there are also stickies in the beginner section. You need to learn about cycling before you get more fish. Also, you should research the fish before you buy them- so you can see if they get along, how big they get, what they eat, etc. When stocking your tank, you need to stick to the 1" of fish per gallon rule to keep things as healthy as possible. I'm not sure how big angels are supposed to get, and it depends on the kind that you have. But, I'm sure they wouldn't be very happy in a 5g. They get very tall and like to have lots of space to swim.
If you have any questions about how cycling works, we are all here to help! This is really the first step to fish keeping.
We just want you to have a successful and healthy tank!
Welcome to MFT!