environment with higher trophic level (eutrophic taxa), higher
pH and moderate nitrogen contents but it is oligosaprobous
species. Belal (2012) reported that C. placentula had high optimum
of total phosphorus (511.5 lg/L) in the River Nile. In the
same time, A. minutissimum satisfied the indicator selection criteria
for ammonium-nitrogen, where it had the highest optimum
value of 564 lg/L. This species classified as a species