A couple of questions regarding Angelfish

1- I think it would be a bit too tight. In good conditions, angelfish can grow up to 6-7 inches.

3-The angelfish could nip at the guppies. If you get a pair, you may regress some of the agression, but in your case, it would be way too crowded for two.

4- Some say that if you get them young, they might not be as nippy. But others have had different experiences too. So I wouldn't rely too much on this being true

5- Like any other fish, good water maintainance and care makes any fish easy to keep. As long as you keep eveything within the parameters and you'll be fine.

6- Unfortunately, I don't think you should. On the upside, since you already have an established tank (I presume), you could simply by a new bigger one, then used some of the stuff you already have to cylce the tank quicker, and get an even nicer display tank with angelfish.

Hope this helps and good luck

i mostly agree with the last post

if you ever want to see baby guppies, don't add an angel... an adult will eat any fish it can fit in its mouth. people forget that angels are indeed cichlids, and they are VERY territorial (especially females)... in a 20 gallon tank, thats pretty much the whole tank, though i see no problem with the cories as they stay out of the middle and top waters.

personally i'd add four or five more cories... they are a very social fish, and you wont see their true behaviour until you get up around 6-8... and this would give you many more options for other neat fish, especially colonies (5+) of tetras.

if you are gung ho about an angel in your twenty, i have a story for you. i did the same thing years ago. the angel killed my favorite pleco (a beautiful bristlenose), and eventually died a premature death.

wait for the angels... a 55 with four of them would be soo much more satisfying.

small angels are neat, but after six months, its not going to look good with an adult... it will start to bother you. it did me

edit: personally i think the minimum for angels is a 29 gallon... the extra topspace and length are necessary. and i'm assuming you have the standard 20 high, (24" long) not the 20 long breeder... if its the 20 long... no way