Doctors were surprised to find a 2 cm long fish in the penis of a 14-year-old boy from India. Apparently, the fish had slipped up the penis and into the boy's bladder.

The patient was admitted to hospital with complaints of pain, dribbling urine and acute urinary retention spanning a 24-hour period. According to the boy, the fish slipped into his penis while he was cleaning his aquarium at home.

Professor Vezhaventhan and Professor Jeyaraman, who treated the boy and later wrote a paper on the case, explain: "While he was cleaning the fish tank in his house, he was holding a fish in his hand and went to the toilet for passing urine. When he was passing urine, the fish slipped from his hand and entered his urethra and then he developed all these symptoms."

After detecting the fish in the boy's bladder, Vezhaventhan and Jeyaraman used a technique known as cystourethroscopy to insert a special set of forceps down the patient's penis. Unfortunately, the fish was just too slippery to grip, so they resorted to using a rigid ureteroscope with a tool attached that is normally used for removing bladder stones.

The fish the urologists removed, which Practical Fishkeeping believes to be a small member of the Betta genus, measured 2cm long and 1.5cm wide.

Vezhaventhan and Jeyaraman report that a range of self-inflicted foreign bodies have been previously removed from the male genitalia and lower urinary tract.

After the removal of the fish the boy's symptoms disappeared, but he was subsequently sent for psychiatric counseling.