Blue paradisefish

Paradise fish .... macropodus opercularis

Perhaps the original 'tropical' fish. People were keeping and breeding these in the UK when the Queen was called Victoria, so it can't be that hard.

They are fine in tropical temperatures, up to about 26 degrees, but they will happily live and breed at room temperature. 

Males in full breeding dress are absolutely stunning, and with their full tail extentions can look much bigger than they actually are. Body size tops out at about 4 inches, but the tail can be just as long so they can look massive when displaying to their lady friends.

They are bubble nesting air breathers, related to gouramis, and hardier, if thats possible. A very overlooked fish which really deserves to be owned by more people. Everyone should have paradisefish.