Fish For Tank

[55gal]

i've had a ten gallon aquarium that i've been using for breeding guppies but when that got out of hand i decided to separate the males and females. i got a 55 gallon tank and put my eight males in that we added seven neon tetras, two angel fish, one oranda? goldfish, one bala shark and a chinese algea eater. the oranda i've had for three months but it has not grown much i was given it from a teacher at the school my mom works at it is about four inches long. i heard they got big although to me it does not seem this one will. i was wondering if you think my goldfish will grow and if you think i should get any more fish. if so what is a good type of fish for this community with small and big fish? i had heard bala sharks were great for this situation and that is why i got one although he may be sick (read "bala shark won't eat" in the tropical fish emergency forum). also does anyone know what live plants are easy to keep and if any of my fish will eat them? i know i have alot of questions but i want to make this tank really good so i was also wondering how much decor i should have in the tank i have eight fake plants two are tall enough to reach the top three are medium in height and three are short but all are pointing straight up and are wavy. i also have a rick formation about six inches across and four inches high with two holes through the center. sorry this post is so long but i'm thankful for an answer to any of my questions.