Abstract
Background:
Protists and helminths are considered the main organisms invading different cultures, especially aquatic organisms. Morphometric characteristics remain the most trustworthy descriptors of species identification or, more broadly, pattern recognition.

Aim:
This study aimed to provide morphological descriptions of the most prevalent Protista and helminths found in various street wetlands in Port Said, Egypt.

Methods:
This study collected three water samples per area each month. The samples were sent to the Parasitology Laboratory at Port Said University, Egypt. The samples were analyzed in two ways according to organism size. Large helminths were observed within 24 h using a microscope, and their movements were recorded. Protists and helminth eggs were isolated by filtering water through a 0.45 μm cellulose acetate filter, followed by centrifugation. The isolated organisms were counted and imaged.

Results:
Nine dominant organisms were identified in the collected samples, including five parasitic species (Protoopalina sp., Balantidium coli, Entamoeba sp., Fasciola sp., and Haemonchus sp.) and four free-living species (Paramecium sp., Euplotes sp., Echiniscus sp., and Aeolosoma sp.). Protoopalina sp. was the most abundant parasite (17.5%), exhibiting a cylindrical, elongated shape (97.3–139µm in length, 30–48µm in width). Euplotes sp. were the free-living organisms (17%), measuring 59.7–66.5 µm in length and 32.1–42.5µm in width, featuring cirri and dark bristles. Paramecium sp., with lengths between 161 and 256 µm, was spindle-shaped and had visible contractile vacuoles. B. coli trophozoites measured 60–107µm in length and 46.5–83.3µm in width, with a large posterior macronucleus. Haemonchus sp. larvae were about 700 µm long, with a distinct tail filament assisting their complex movement.

Conclusion:
The street wetlands in the surveyed area contain various free-living and pathogenic taxa. There is a need to link the presence of these organisms to physicochemical analyses. Future studies should prioritize broader geographic sampling, the integration of molecular techniques, and the exploration of host-parasite relationships.

Key words: Free- living, Parasites, Morphometric features, Richness, Movement