The two most important things to avoid are heat and chlorinated tap water.
Water: As soon as the leeches are received, place them in a Leech Mobile Home or other clean, suitable container with sufficient new water. Use distilled, non-chlorinated or bottled water. Do not use tap water.
MAINTAIN HEALTHY LEECHES BY CHANGING THE WATER EVERY OTHER DAY.
Use 2 grams of HIRUDO salt for each gallon of distilled, non-chlorinated or bottled water. Prior to replacement, check and maintain the same water temperature. HIRUDO salt is to be used only as an additive to the water in which the live leeches are kept or stored.
Temperature: Keep leeches cool, 42-45 F (5-7 degrees C). Avoid temperatures above 68 F (20 C) and never place them in direct sunlight. When used in heated hospital wards, take special care to keep leeches in a cool place. Avoid sudden changes in temperature when transferring leeches from one container to another.
Container: Since leeches are amphibious and like to crawl about, a lid is essential. Perforations are advised, but they must be very small because the elastic leech body is capable of going through remarkably small openings. A cloth cover tightly secured with string, rubber band or tape is useful. Do not overcrowd - no more than 50 leeches should be in a 2-gallon container.
Disposal: Some hospitals use the incinerator, after narcotization in 70% alcohol, to dispose of leeches.