[1] Ceratothoa steindachneri has an oval to rounded body and is generally stocky.

[2] Ceratothoa steindachneri is found in the northern Atlantic Ocean and the Mediterranean Sea.

[2][3] It was first found in British waters at Whitsand Bay, Cornwall, in 1996 in the lesser weever fish.

[4] It is a generalist species that can parasitise a wide range of fish species, including the shortnose greeneye (Chlorophthalmus agassizi), lesser weever fish (Echiichthys vipera), red porgy (Pagrus pagrus), comber (Serranus cabrilla), painted comber (Serranus scriba), brown comber (Serranus hepatus), annular seabream (Diplodus annularis), and common two-banded sea bream (Diplodus vulgaris).

[4][3] Ceratothoa steindachneri has also been reported on Raja asterias, R. polystigma, and R. albas, but these records are yet to be confirmed, as they are most likely the result of trawl transfers.