So I’ve had this 13.5 gallon tank for about a year now and I’ve had a pair of clowns and a court jester goby for most of it. Recently the court jester died (looked up why after and apparently most of them just starve themselves for no reason) I would like to add a new fish so any suggestions? I was thinking of a royal gramma but I heard but I head they can be aggressive, or if it’s possible (I doubt it) I really like Bangai cardinal fish so I would love a pair of them if possible