I want more fish, but I not sure what else to put in my tank with my existing fish in order not to disrupt the community. I currently have a blue tang, clown fish, goby, blue springer, 2 pajama cardinals, 3 green chromis, 1 peppermint shrimp, and 1 sea urchin. I have a 90 gallon tank. Is that enough fish or can I add more? If yes, what do you recommend?