i currently have a 20 gallon tank with 1 senior blue gourami. i have just added 3 silver tip tetras. i plan on adding 3 more next week after my to be expected mini cycle. what would make good tank mates for my fish? my gourami is quite aggressive so i need something that can hold its own. i would really like to get something very colorful - any colors other than blue and yellow. please let me hear your opinions!