There are some issues with this. First, it is just not fair to the angelfish to put it in isolation. This species is what we term shoaling or some term it schooling. What it means is that the fish live together in groups, with this species the groups are usually around 30. They develop an hierarchy, and pairs will generally form to spawn. The pair will claim a territory, and the others in this group will remain outside. To puta lone angelfish in any tank is as I said simply not fair to the fish because it expects the group and associated behaviours, this is partially what makes the species unique. It has needs and expectations, and these should be provided.
There is also the issue of tankmates, the other fish that angelfish will have to manage with. I won't go into this, because as other members have noted, this tank does not have the depth for angelfish, regardless of the above. I would strongly suggest you consider other fish. If you want something that sort of "stands out," there are some peaceful gourami which have similar behaviours (males are territorial) but some of the species are much more peaceful.
Another totally different issue involves the water parameters of your source (tap) water. These are the GH (general hardness), KH (carbonate hardness or Alkalinity), and pH. The three are closely connected. You may be able to ascertain from the website of your water authority (if you are on city water, as opposed to a private well) these numbers. The GH and pH especially are important because they can impact fish, depending.