We have a lot of 10 Ichtheus Fish Pins nos.  They are missing the metal pinch back to cover the pins - these can be purchased separatly at many places.  These date somewhere between the 1980's - early 2000's.  I purchased them straight from the mill that was closing who manufactured them.  They measure about 7/8" x 3/8"

10 Ichtheus Fish Pins nos