Plz Suggest What new fish to add to my Tank

Question
I have a 4*1.5*1.5 ft tank. It houses two zebra Angels(4 inch each), two (3inches) and one (6 inch) Bala sharks, two red and two yellow Blood Parrots(4 inches each) and two Goldfishes(6 inches each) for the past 8 months. Goldfishes are living in harmony with others till date.
The tank receives sunlight for 4-5 Hrs a day and there is a light yet persistent problem of Brown Algae. I change 25-30% water on weekly basis along with vacumming.
I have four issues.
1) I want to add fishes to the tank, which ones would be compatible as I am aware that I already have a wrong combination in the tank. My family wants to add more of colorful and decorative fishes.Plz guide.
2) The 6 inch Bala Shark used to be very playful but ever since its companion died and I replaced it with two (3 inches) bala sharks, I have never seen it playing again in the tank. Should I add more bala sharks and if yes, then how many & what size?
3) The 2 Red and 2 Yellow Blood Parrots have lost their color within one month of being introduced into the tank 8 months ago and now all look pale pink. Now even though tank is cycled they are yet to regain their natural color.I am feeding them with Aquadene-Ruby red pellets and Sera- Red Parrot pellerts in the Ration 60:40 two times a day. Kindly suggest how to proceed.
4) The two angels are always at loggerheads and fighting each other. What could be the reason and solution.


Answer
Hi Jagpreet:  I can not believe the angels or the blood parrots have not killed the goldfish.

1) albino plecostomus, hatchet fish, neon tetra, gold dojo loach, heat light tail light tetra, zebra danios... etc.  I would not add more then six more small fish to your tank.

2) I would not add any more bala sharks

3) color loss can be part of the temperature of the tank... this is where mixing goldfish and tropical fish becomes an issue... to keep both the temperature must be mild... mild temperature means loss of color in tropical fish...

4) the angels are fighting over territory as you have too many mid level fish...such as angels. separate them.  

dave