This paper provides an account of twelve intertidal species of hydroids reported from the State of Gujarat, north-west India. Six of them constitute new records for the coast of Gujarat, and four are reported for the first time from waters of India. Also reported for the first time from Indian waters are the genera Zyzzyzus and Nemalecium.

This is the first record of Grammonus robustus from Indian waters. Five specimens measuring 132–233 mm standard length were collected from the by-catch landed by a deep sea trawler from waters 150 to 200 m deep off the Tuticorin coast in the Gulf of Mannar. The detailed morphometric and meristic characters are compared to known G. robustus material.

The serranid fish Liopropoma lunulatum (Guichenot, 1863) and Plectropomus laevis (Lacépède, 1801) were recorded from Cochin fisheries harbour, Kerala in March 2012, constituting new records for Indian waters. Morphometric and meristic characters of the specimens were similar to those reported elsewhere for the species. Distinguishing characters and colour patterns of the two species are discussed. The present record indicates a marked extension of their range of distribution from their type localities.

In the present study, a centric diatom Chaetoceros minimus is reported for the first time from the Indian waters. This record will contribute to the phytoplankton checklist of Indian seas. Morphological characteristics and distribution of the species are provided.

Polka-dot ribbonfish Desmodema polystictum was recorded for the first time from Indian waters. A single specimen of D. polystictum (107 cm total length and weighing 480 g) was collected from Tharuvaikulam landing centre, north to Tuticorin, on the south-east coast of India during September 2010. The distinguishing characters of the species from other species of the family are discussed. Morphometric and meristic characters of D. polystictum are presented in this paper. With the present report, the distribution area of this species now extends to the Indian waters.