This research paper presents the microbial and hydrobiological indicators and the physicochemical quality of water samples from a lentic ecosystem in Ibeno LGA, Nigeria, after sixteen (16) years of an aviation fuel spill. Using culture-dependent methodologies, the hydrocarbonoclastic bacterial and fungal counts (HBC & HFC) ranged from 3.4 x 10 4 to 1.2 x 10 5 cfu/l and 4.7 x 10 3 to 1.8 x 10 4 cfu/l, respectively with the ratios of total heterotrophic bacterial counts to HBC and total fungal counts to HFC ranging from 8 to 12% and 15 to 22%, respectively. Predominant bacterial indicators included Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus varians and Enterobacter aerogenes while predominant fungal indicators included Aspergillus niger, A. terreus, Candida sp, Saccharomyces sp, Phoma sp. and Botrytis sp. Predominant zooplanktons in the sampled area were rotatoria while the least were nematodes and followed the trend: Rotatoria > Copepoda > Cladocera > Nematoda. Water samples from the area showed evidence of oil sheen when disturbed; with pH values (6.2 to 7.8) tending generally towards neutral. Total petroleum hydrocarbon (TPH) from this aviation fuel-contaminated lentic system ranged from 81.5 mg/l to 505.2 mg/l. Dissolved oxygen (DO) were generally low with high BOD and COD of 46.3 mg/l and 321.1mg/l, respectively. Other physicochemical parameters were typical of lentic ecosystems in the Niger Delta region, Nigeria. The impact of this and many other spills are enormous. This confirms that it takes a long time for recovery once the environment is polluted.