check sexing male last picture... tail would be more yellow though.
, could be irrebusco need to see body shape front on, it does not appear to have red eyes.
There are now considered to be two species of pea or dwarf puffer, may be there are regional variations. C. imitator was only identified in 1999 and these comments are interesting...The C. imitator male is identifiable by a "keel" and "comb" created with the ability to erect their dorsal and ventral ridges. .. I have an adobe article somewhere that describes the details more explicitly.