A hint on how to create some really weird mutations and have fun
 doing so : 
 
 El-Fish stores its fish as roe in binary files. When you click on
 Restore, the software converts a roe file back into a fish. But you
 can also convert almost any binary or ASCII File-a customer database,
 a budget spreadsheet, a health-benefits memo into a fish. Just copy
 the file with new extension .ROE. (Don't use EXE or COM Files.)
 After loading El-Fish, Click on Restore From and find the fishy new
 file. It will create one or more mutant aquatic life forms. I tried a
 file containing Earned Run Average statistics for American League
 pitchers, and as expected, the fish created was extremely ugly.