Telliposoidea (Gerneck) + Scenedesmus bijuga (Turpin) as green algae at the beginning of the production season (or before the preferable time of cyanobacteria growing) to propagate and prevent the growth of harmful cyanobacteria in the Nile tilapia culture via glass aquaria. Indoor experiment was carried out in natural light using 12 glass aquaria as four groups (3 replicates each). Ten Nile tilapia fingerlings were stocked (Oreochromis niloticus) in each aquarium.
The cyanobacteria were not appeared in the fish aquaria which were seeded or inoculated with Chlorella + Scenedesmus 20 x 103 cells ml-1 (T3) at day 5 and 10. The cyanobacterial count was lower in the second treatment (T2). Significant differences were observed between the cyanobacterial count on day 5 and 10 in the control aquaria and those inoculated with Chlorella + Scenedesmus sp. (p < 0.05). Higher counts of green algae were observed in aquaria inoculated with the highest dose of Chlorella + Scenedesmus sp. (T3). Generally, the green algal count in control aquaria was the lowest, followed by those treated with 10 x 103 cells ml-1 Chlorella + Scenedesmus sp. (T1). No significant differences were observed in the green algae and cyanobacteria counts on day 5 and 10 between T2 and T3 (P < 0.05).
The present experiment showed that the presence of Chlorella + Scenedesmus sp. is sufficient to control the growth of cyanobacteria for 10 days period in the Nile tilapia culture.