In this paper we make a study of five monogenetic trematodes of the family Capsalidae Baird, 1853. We describe two new species of the genus Benedenia Diesing, 1858, Benedeniinae Johnston, 1931: Benedenia pompatica sp. n., which is very similar to Benedenia sciaenae (Beneden, 1852) abd differs from it mainly by the structure of the second and third pair of the haptoral hooks; and Benedenia innobilitata sp. n. near to Benedenia jaliscana Bravo-Hollis, 1951 does not have the armed cirrus, proper to the last and the structure and position of the vagina is also a considered characteristic. For the subfamily Trochopodinae (Price, 1936) we give new hosts: Lepidotrigla cavillone for Trochopus pini (Beneden & Hesse, 1863) and Serranus cabrilla for Megalocotyle grandiloba Paperna & Kohn, 1964, and we also redescribe and illustrate them. Under this subfamily we also propose a new species of the genus Allomegalocotyle (Robinson, 1961) by the morphology of the haptoral hooks, the position of the vaginal aperture and the big external seminal vesicle.