Production of Daphnia similis Claus, 1876 using wastewater from tilapia cultivation in a biofloc system Clarissa Vilela Figueiredo da Silva Campos 1 & Renata da Silva Farias 1 & Suzianny Maria Bezerra Cabral da Silva 2 & William Severi 3 & Luis Otavio Brito 4 & Alfredo Olivera Gálvez 1 Received: 30 November 2018 /Accepted: 25 September 2019/ # Springer Nature Switzerland AG 2019 Abstract This research evaluated the growth of Daphnia similis in wastewater from Nile tilapia (Oreochromis niloticus) farmed in a biofloc system (carbohydrate:nitrogen of 12:1). During 30 days, physical-chemical and growth variables were measured in the following treatments: DCWC—D. similis growth in clear water with the addition of C. vulgaris (autotrophic culture); DB—D. similis growth in biofloc wastewater from Nile tilapia farmed without the addition of C. vulgaris (mixotrophic culture); and DBC—D. similis growth in biofloc waste- water from Nile tilapia farmed with the addition of C. vulgaris (mixotrophic culture). The biofloc wastewater (DB and DBC) underwent significant changes in water quality (P < 0.05) that influenced the growth of D. similis, which reached two population cycles. Statistical differences (P < 0.05) between the treatments were found for specific growth rate, doubling time, maximum average density (MAD), and yield, in which DBC achieved a yield of 136 ± 31 ind L -1 day -1 and a MAD 8-fold higher than in DCWC in the first cycle and did not differ (P > 0.05) from DB in relation to MAD in the second cycle. Thus, wastewater from Nile tilapia cultivation in a biofloc system as a culture medium for raising D. similis, with the addition of C. vulgaris, proved to be a promising option for producing live food for aquaculture. Keywords BFT . Cladoceran . Live food . Microalgae . Oreochromis niloticus . Mixotrophic Abbreviations DB D. similis growth in biofloc wastewater from Nile tilapia farmed without the addition of C. vulgaris DBC D. similis growth in biofloc wastewater from Nile tilapia farmed with the addition of C. vulgaris DCWC D. similis growth in clear water with the addition of C. vulgaris DO Dissolved oxygen DT Doubling time Aquaculture International https://doi.org/10.1007/s10499-019-00470-7 * Clarissa Vilela Figueiredo da Silva Campos clarissavilela19@gmail.com Extended author information available on the last page of the article