SQL- Invalid identifier when creating foreign key- SQL Error: ORA-00904

Question

Whenever I run the script I keep getting this error:

Error report - SQL Error: ORA-00904: "HORSE_ID": invalid identifier 00904. 00000 - "%s: invalid identifier" *Cause:
*Action:

I am trying to make a foreign key linking the HORSES and MEDICAL table. I think everything looks correct. Can someone let me know what I have done incorrectly? I am using Oracle SQLDeveloper.

 CREATE TABLE HORSES (
        Horse_ID varchar(10) NOT NULL Primary Key,
        Name varchar(50) NOT NULL,
        Height varchar(50) NOT NULL,
        Weight varchar(50) NOT NULL,
        Breed varchar(50) NOT NULL,
        Surrender varchar(50) NOT NULL,
        Seize varchar(50) NOT NULL,
        Score varchar(15) NOT NULL,
        Aq_Date varchar(10) NOT NULL,
        Ridable varchar(50) NOT NULL,
        Trim varchar(50) NOT NULL,
        Age varchar(50) NOT NULL
    );

    /* MEDICAL */
    /* ------------------------------------------------------------ */

   CREATE TABLE MEDICAL (
       Med_ID varchar(50) NOT NULL primary key,
       Feed_Ins varchar(4000) NOT NULL,
       Special_Vet varchar(2000) NOT NULL,
       Coggins varchar(50) NOT NULL,
       Vaccs varchar(50) NOT NULL,
       Deworm varchar(50) NOT NULL,
    CONSTRAINT Horse_ID_HORSES_FK FOREIGN KEY (Horse_ID) REFERENCES HORSES(Horse_ID)
   );

Answer 1

You don't have a horse_id column in medical, how do you want it to be fk for that table?