Possible Clues:

• Odd fellow had fish before German fellow left
• Eccentric old gent
• Old bloke is scrounger, offering nothing for article
• Old-fashioned geezer
• Old man, fish and short man standing
• (Old) man
• Is that the fish old Reginald is back with?
• Oldster, affectionately
• Programmer brings in good old chap
• A senior computer programmer grasps Prolog at last