As specialists in leech biology we have prepared the following to help those of you directly involved in caring for the medicinal leech Hirudo medicinalis . The two most important things to avoid are heat and chlorinated tap water.
Leeches can live for months on a blood meal so feeding is unnecessary.
Special care and attention should be taken if the leeches are to be used in a heated hospital ward. Keep them as cool as possible until they are needed. Never put leeches into direct sunlight. The water is now ready for use. Aeration is unnecessary.