Originally Posted by Chief_waterchanger

Explaination is as follows:

Your hyperlink in your signature says it is a 40g tank.........

2 goldfish get to 8-10inches a piece and need atleast the 40g to themselves
2 angelfish need atleast 20g for themselves
2 bala sharks get to 1ft a piece
tetras are smaller fish that will be harassed by the larger fish (white scratch is probably a battlewound)
the zebra danio need to be in schools of 5-6 or more
the pleco I hope is not a common, it gets to 1ft and needs atleast a 55g tank

So basically you have a grossly overpopulated tank.

The overpopulation of the tank (I am assuming based on your signature and what it says is in the tank) is the root of all of your problems. The 'white scratch' is probably a wound that is trying to heal. The 'reddness' is probably infected wounds. The angelfish most certainly can kill anything their size and smaller, without too much trouble, as can most fish. Methylene blue is used to treat infections.

The territorial issues stem back, yet again, to the overpopulation of the tank.

In the wild if a fish gets territorial and harasses another the weaker of the two goes elsewhere, if they are stuck in a glass box they don't have that option available to them. I would suggest either getting more tanks or selling/returning whatever fish you can.