Euhaplorchis californiensis

are eaten by

• Global Biotic Interactions: Leukoma staminea (Conrad 1837)
• Global Biotic Interactions: Quietula y-cauda (Jenkins & Evermann 1889) (American shadow goby)
• Global Biotic Interactions: Rexithaerus secta (Conrad 1837)
• Global Biotic Interactions: Ilypnus gilberti (Eigenmann & Eigenmann 1889) (Cheekspot goby)
• Global Biotic Interactions: Laevicardium substriatum (Conrad 1837)

are parasitized by

• Global Biotic Interactions: Phocitremoides ovale
• Global Biotic Interactions: Phocitremoides ovale
• Global Biotic Interactions: Acanthotrema hancocki (Martin 1950) Lafuente, Roca & Carbonell 2000
• Global Biotic Interactions: Acanthotrema hancocki (Martin 1950) Lafuente, Roca & Carbonell 2000
• Global Biotic Interactions: Mesostephanus appendiculatus

are preyed upon by

• Global Biotic Interactions: Leukoma staminea (Conrad 1837)
• Global Biotic Interactions: Rexithaerus secta (Conrad 1837)
• Global Biotic Interactions: Pandion haliaetus haliaetus (Linnaeus 1758)
• Global Biotic Interactions: Polydora nuchalis Woodwick 1953 (Polychaete)
• Global Biotic Interactions: Butorides virescens (Linnaeus 1758) (Green Heron)

have host

• Global Biotic Interactions: Cerithidea californica
• Global Biotic Interactions: Cerithidea californica
• Global Biotic Interactions: Nycticorax nycticorax (Linnaeus 1758) (Black-crowned Night Heron)
• Global Biotic Interactions: Ardea herodias Linnaeus 1758 (Great Blue Heron)
• Global Biotic Interactions: Podilymbus podiceps (Linnaeus 1758) (Pied-billed Grebe)

parasitize

• Global Biotic Interactions: Phocitremoides ovale
• Global Biotic Interactions: Larus californicus Lawrence 1854 (California Gull)
• Global Biotic Interactions: Egretta rufescens (Gmelin & JF 1789) (Reddish Egret)
• Global Biotic Interactions: Recurvirostra americana Gmelin & JF 1789 (American Avocet)
• Global Biotic Interactions: Fundulus parvipinnis Girard 1854 (California killifish)