List of freshwater leeches of Britain

There are 18 species of freshwater leech found in Britain.

Rhynchobdellida

Rhynchobdellida is an order of "jawless" leeches with a pharynx which they evert to attack their hosts.

Piscicola siddalli in Mold, Wales.

Family Piscicolidae

• Piscicola geometra — a common species that is best known for parasitizing freshwater fishes, although they also sometimes attack amphibians, molluscs, and other worms. The species is native to the Palearctic realm, but were introduced to the Nearctic, and have been reported from South America as well. The leeches are not permanent parasites and are free-living during their breeding period, and live in fish ponds, lake shores, and watercourses with a strong current. In the British Isles, they are common in England, southern Ireland, and Wales, but rare in northern Ireland and Scotland. A 1982 recording scheme showed it to be the sixth-most collected species of freshwater leech in the British Isles.
• Piscicola siddalli — the smallest species of British freshwater leech, sometimes measuring just 7 millimetres (280 mils) at rest. It was discovered for the first time in 2006 living in the River Ure, where it was parasitizing grayling. The discovery was not published until 2012.

Family Glossiphoniidae

• Batracobdella algira — a European species first discovered in the British Isles from southern England in 2024. It parasitizes amphibians, and was observed infesting Bufo bufo and Rana temporaria. Molecular analysis of the leeches collected connected the leeches to Tunisian populations, and the discoverers concluded that the leeches were probably not native to the region. In general, B. algira prefers warmer habitats and is found in the southern Palearctic realm.
• Batracobdella paludosa — a rare species in the UK, and the thirteenth-most collected in the 1982 report. It was first described from Britain in 1953. The species is "widespread but rare", and parasitizes gastropods in ponds, lakes, streams, and rivers. It is found in the Palearctic realm.
• Glossiphonia complanata — also known as the greater snail leech, this is a very common species in the UK – in fact, the 1982 report found it was the most-recorded species of freshwater leech in the British Isles.
• Glossiphonia heteroclita

  

  Glossiphonia verrucata in Germany.

• Glossiphonia verrucata
• Helobdella stagnalis
• Hemiclepsis marginata
• Placobdella costata

Arhynchobdellida

Family Hirudinidae

• Haemopis sanguisuga
• Hirudo medicinalis

Family Erpobdellidae

• Erpobdella lineata
• Erpobdella testacea
• Erpobdella octoculata
• Trocheta bykowskii
• Trocheta subviridis