Children (13 direct children, 13 direct and indirect children):
Hydrocolus sahlbergi
Hydrocolus rupinus
Hydrocolus oblitoides
Hydrocolus rubyae
Hydrocolus stagnalis
Hydrocolus heggiensis
Hydrocolus deflatus
Hydrocolus rufiplanulus
Hydroporus rufiplanulus
Hydrocolus filiolus
Hydrocolus oblitus
Hydrocolus persimilis
Hydrocolus paugus
Hydrocolus rubyi