Stocking A 55 Gallon (Cycled) Aquarium

[AnthonyDeQuinzio]

Hello all,
 
I could use some assistance stocking my 55 gallon aquarium. I would like to stick to the 1 inch / gallon rule: Here is some information along with what is currently in the tank:
 
Tank:
Fully cycled
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: 10 ppm 
pH: 7.6
Using the fancy API kit
GH/KH: Unsure. Tap water is on the hard side.
Temperature: 80 degrees Fahrenheit
Filtration: 2 HOB (AquaClear 110 and AquaClear 50)
Media: 110 - sponge, purigen, bio balls; 50 - sponge and bio balls
 
Stock:
5 x Tiger Barb (lost two during power outage) so down to 3
2 x Golden Gourami
2 x Bristlenose catfish
1 x Rainbow shark
 
The Tiger Barbs generally pester one another and leave the other fishes alone. The Gourami's nip at one another occasionally; they spend their time in opposite sides of the tank. The Rainbow nipped at the catfish before I upgraded to the 55 gallon (originally all were housed in a 20 gallon together). I understand that Tiger Barbs are not the epitome of community tank mates and the Rainbow will likely become aggressive later on...but there has to be something that will serve as a great addition to the tank, right? 
 
Your thoughts and opinions are greatly appreciated. 

 

[Mark Z.]

Maybe some denison barbs? They are peaceful, active and colorful.

 

[Lateral Line]

>>> Tiger Barbs are not the epitome
 
Certainly true if kept in small numbers, I'd up their number.