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Aim Non-native fish species have been closely related to serious damage to aquatic biodiversity due to their negative effects on native fauna. We aim to report the first and alarming occurrence of the non-native catfish “jaú” Zungaro jahu in the Iguaçu River basin above the Iguaçu Falls, a high-endemism Neotropical ecoregion for fish. Methods Fish samplings were taken with a bottom gill net in the Segredo Reservoir, where they were anesthetized in benzocaine hydrochloride and fixed in formaldehyde in the field, later identified in the laboratory and housed at the Museu de História Natural do Capão da Imbuia (MHNCI). Results Our recent samplings in the Iguaçu River basin recorded one non-native individual of the catfish “jaú” Zungaro jahu in the Segredo Reservoir. Conclusions We mainly intend to alarm about the risk of expansion of the occurrence of this non-native species throughout the cascading reservoirs in the Iguaçu River where it could potentially develop serious damage to the trophic chain, predation of small-sized endemic species, and competition, especially in the sites where the endemic and endangered pimelodid “surubim-do-iguaçu” (Steindachneridion melanodermatum) maintains viable populations, currently restricted to the Lower Iguaçu River basin exhibiting recent signs of a population bottleneck. Resumo: Objetivo Espécies de peixes não nativas têm sido intimamente relacionadas aos sérios danos à biodiversidade aquática devido aos efeitos negativos sobre a fauna nativa. Nosso objetivo é relatar a primeira e alarmante ocorrência do bagre não nativo “jaú” Zungaro jahu na bacia do rio Iguaçu acima das Cataratas do Iguaçu, uma ecorregião neotropical com alto endemismo de peixes. Métodos As amostragens dos peixes foram realizadas com rede de emalhar de fundo no Reservatório de Segredo, onde foram anestesiados em cloridrato de benzocaína e fixados em formol em campo, posteriormente foram identificados em laboratório e depositados no Museu de História Natural do Capão da Imbuia (MHNCI). Resultados Nossas amostragens recentes na bacia do rio Iguaçu registraram um indivíduo não nativo do bagre “jaú” Zungaro jahu no Reservatório de Segredo. Conclusões Pretendemos, principalmente, alertar sobre o risco de expansão da ocorrência desta espécie não nativa ao longo da cascata de reservatórios do rio Iguaçu, onde potencialmente poderá desenvolver sérios danos à cadeia trófica, predação de espécies endêmicas de pequeno porte e competição, especialmente nos locais onde o pimelodídeo endêmico e ameaçado de extinção “surubim-do-iguaçu” (Steindachneridion melanodermatum) mantém populações viáveis, atualmente restrita à bacia do Baixo rio Iguaçu, exibindo sinais recentes do efeito de gargalo.

Moenkhausia australe (Eigenmann, 1908) Moenkhausia australe Eigenmann 1908: 103 [original description]. Moenkhausia sanctaefilomenae — Reis et al. 2003: 150. Material examined. Table 2; Figure 5H. Deep body; terminal mouth; inner row of premaxilla with 5 teeth, outer with 3 or 4, dentary with 9–12 and maxilla with 1 or 2 teeth. Lateral line complete, with 19–26 pored scales; longitudinal series with 24–26 scales; transversal series above lateral line with 4, 4½ or 5 scale rows and below with 3, 3½ or 4 scale rows. Dorsal fin with 11, pectoral fin with 11–13, pelvic fin with 8, anal fin with 24–27 and caudal fin with 19, total rays. Ground color silvery; scales with dark-brown border, conferring reticulated pattern to body; 1 dark-brown humeral spot; anterior half of caudal peduncle with light area. Hyaline fins, except caudal fin. Moenkhausia australe is morphologically similar to M. forestii and M. sanctaefilomenae, but can be distinguished from them by having lateral line completely pored, rarely disrupted (vs lateral line incompletely pored, in M. forestii and M. sanctaefilomenae). Moenkhausia bonita Benine, Castro & Sabino, 2004 Moenkhausia bonita Benine et al. 2004: 68, fig. 1 [original description]. Hemigrammus marginatus — Graça and Pavanelli 2007: 63. Material examined. Table 2; Figure 5I. Elongated body; terminal mouth; inner row of premaxilla with 5 teeth, outer with 2–5, dentary with 4 and maxilla with 2 or 3 teeth. Lateral line complete, with 29–34 pored scales; transversal series above lateral line with 5 scale rows and below with 3 scale rows. Dorsal fin with 11, pectoral fin with 12–13, pelvic fin with 8, anal fin with 24–26 and caudal fin with 19, total rays (Benine et al. 2004). Ground color silvery to pale yellow; dark-brown longitudinal stripe from opercle (conspicuously from vertical through dorsal-fin origin) to median caudal-fin rays; distal portion of caudal-fin lobes equally dark brown., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on pages 369-370, DOI: 10.15560/14.2.363, {"references":["Eigenmann CH (1908) Preliminary descriptions of new genera and species of tetragonopterid characins. (Zoological Results of the Thayer Brazilian expedition). Bulletin of the Museum of Comparative Zoology 52: 91 - 106.","Reis RE, Kullander SO, Ferraris CJ (2003) Check list of the freshwater fishes of South and Central America. EDIPUCRS, Porto Alegre, 742 pp.","Benine RC, Castro RMC, Sabino J (2004) Moenkhausia bonita: a new small characin fish from thr Rio Paraguay basin, southwestern Bra- zil (Characiformes: Characidae). Copeia 2004: 68 - 73. https: // doi. org / 10.1643 / CI- 03 - 008 R 1","Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp."]}

Aphyocharax dentatus Eigenmann & Kennedy, 1903 Aphyocharax dentatus Eigenmann and Kennedy 1903: 516 [original description]— Britski et al. 1999: 45; Graça and Pavanelli 2007: 86, 88. Material examined. Table 2; Figure 5B. Elongated body; terminal mouth, slightly prognathous; premaxilla with 4–8 teeth, dentary with 9–23, and maxilla with 8–17 teeth. Lateral line incomplete, with 8–13 pored scales; longitudinal series with 36–42 scales. Dorsal fin with 9–11, pectoral fin with 10–14, pelvic fin with 7–8, anal fin with 16–22, and caudal fin with 19, total rays (Lima 2003). Ground color silvery; diffuse, oval transversely elongated, humeral spot; no other dark marks on body and fin. Caudal fin red, other fins hyaline to yellowish.

Rhamdia quelen (Quoy & Gaimard, 1824) Rhamdia quelen — Graça and Pavanelli 2007: 149; Hoffmann et al. 2015: 4, fig. A3.C; Bifi et al 2017: 4, fig. 2.16. Material examined. Table 2. Elongated body; terminal mouth; premaxilla and dentary with several diminute and viliform teeth. Dorsal fin with 7, pectoral fin with 8–10, pelvic fin with 6 and anal fin with 14–15, total rays. Ground color beige to brown; some specimens can present scattered dark brown chromatophores on body; dark fins., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on page 374, DOI: 10.15560/14.2.363, {"references":["Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp.","Hoffmann AC, Nascimento RHC, Shibatta OA (2015) Fish fauna from tributaries throughout the Tibagi river basin, upper Parana, basin, Brazil. Check List 11: 1815. https: // doi. org / 10.15560 / 11.6.1815","Bifi AG, Dias AC, Frota A (2017) Fish species (Osteichthyes: Acti- nopterygii) from two tributaries of the Rio do Peixe basin, Tupa municipality, Sao Paulo state, Brazil. Check List 13: 2063. https: // doi. org / 10.15560 / 13.2.2063"]}

Pyrrhulina australis Eigenmann & Kennedy, 1903 Pyrrhulina australe Eigenmann and Kennedy 1903: 508 [original description]. Pyrrhulina australis — Graça and Pavanelli 2007: 107. Material examined. Table 2; Figure 5S. Elongated body; terminal mouth; inner row of premaxilla with 9–12 and outer row with 4–6 teeth, inner row of dentary with 8–12 and outer row with 4–5, and maxilla with 1 or 2 teeth. Lateral line absent; longitudinal series with 20–25 scales; transversal series with 6–8 scale rows. Dorsal fin with 9 or 10, pectoral fin with 11 or 12, pelvic fin with 9 or 10, anal fin with 10 or 11, and caudal fin with 19, total rays. Ground color pale brown; dark brown longitudinal stripe from the anterior portion of the dentary, through orbit, to opercle; yellowish fins; black irregular blotch on the dorsal fin. Some specimens can present few or many dark blotches on body., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on page 371, DOI: 10.15560/14.2.363, {"references":["Eigenmann CH, Kennedy CH (1903) On a collection of fishes from Paraguay, with a synopsis of the American genera of cichlids. Proceedings of the Academy of Natural Sciences of Philadelphia 55: 497 - 537.","Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp."]}

Cichlasoma paranaense Kullander, 1983 Cichlasoma paranaense Kullander 1983: 241, Fig. 1 [original description]— Graça and Pavanelli 2007: 203; Bifi et al. 2017: 4, Fig. 2.29. Material examined. Table 2; Figure 5Y. Deep body; terminal mouth; premaxilla with 2 or 3 and dentary with 3 or 4 teeth rows. Upper lateral line with 14–17 pored scales, lower lateral line with 5–8 pored scales and longitudinal series with 22–23 scales. Transversal series above upper lateral with 2½–4 and below lower lateral line with 5–7 scale rows. Dorsal fin with XIII–XV, 10–15, pectoral fin with 12–13, pelvic fin with I,6 and anal fin with III, 8–10 total rays (Kullander 1983). Ground color iridescent green; dark brown transversal bars; dark-brown rounded blotch, slightly below upper lateral line; dark brown blotch on superior portion of caudal peduncle., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on page 373, DOI: 10.15560/14.2.363, {"references":["Kullander SO (1983) A revision of the South American cichlid genus Cichlasoma (Teleostei: Cichlidae). Swedish Museum of Natural History, Stockholm, 296 pp.","Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp.","Bifi AG, Dias AC, Frota A (2017) Fish species (Osteichthyes: Acti- nopterygii) from two tributaries of the Rio do Peixe basin, Tupa municipality, Sao Paulo state, Brazil. Check List 13: 2063. https: // doi. org / 10.15560 / 13.2.2063"]}

The ichthyofauna from 3 streams (Água Boa, Perobão, and Santa Maria) to the lower Iguatemi River were inventoried, which is located in the upper Paraná river basin, in Mato Grosso do Sul state, Brazil. Sites in the upper, intermediate, and lower portions of each stream were quarterly electrofished from March to December 2008. All sampled fish (n = 6,816 individuals) represented 43 species of 5 orders, and 16 families. The most abundant species was Phalloceros harpagos (63.5%), followed by Astyanax aff. paranae (10.6%), Hypostomus ancistroides (5.9%), Gymnotus inaequilabiatus (3.4%), and Knodus moenkhausii (2.7%). Despite the high ichthyofauna richness in the lower portion of Iguatemi River, the need to implement and/or expand soil conservation practices and riparian forest restoration is of utmost importance to maintain these populations in the long term.

Crenicichla britskii Kullander, 1982 Crenicichla britskii Kullander 1982: 642, fig. 7 [original description]— Graça and Pavanelli 2007: 204, 205; Bifi et al. 2017: 4, fig. 2.30. Material examined. Table 2; Figure 5Z. Elongated body; terminal mouth; premaxilla and dentary with arranged in several teeth rows. Upper lateral line with 20–22 pored scales, lower lateral line with 7–9 pored scales and longitudinal series with 33–40 scales. Transversal series above upper lateral with 3–4½ and below lower lateral line with 7–9 scale rows. Dorsal fin with XVI, 14–16, pectoral fin with 14 or 15, pelvic fin with I,5 and anal fin with III, 9–11 total rays (Kullander, 1983). Ground color greyish to greenish; dorsum with dark transversal bars; dark suborbital stripe; dark brown discontinuous longitudinal band, sometimes inconspicuous, from snout to caudal peduncle; black rounded humeral blotch; black rounded ocelli on caudal-fin base. Dorsal, anal and caudal fins with light spots; pectoral and pelvic fins yellowish or hyaline., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on page 373, DOI: 10.15560/14.2.363, {"references":["Kullander SO (1982) Cichlid fishes from the La Plata basin. Part III. The Crenicichla lepidota species group (Teleostei: Cichlidae). Revue Suisse de Zoologie 89: 627 - 661. https: // doi. org / 10.5962 / bhl. part. 82465","Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp.","Bifi AG, Dias AC, Frota A (2017) Fish species (Osteichthyes: Acti- nopterygii) from two tributaries of the Rio do Peixe basin, Tupa municipality, Sao Paulo state, Brazil. Check List 13: 2063. https: // doi. org / 10.15560 / 13.2.2063","Kullander SO (1983) A revision of the South American cichlid genus Cichlasoma (Teleostei: Cichlidae). Swedish Museum of Natural History, Stockholm, 296 pp."]}

Astyanax aff. fasciatus (Cuvier, 1819) Chalceus fasciatus Cuvier 1819: 352, pl. 26 [original description]. Astyanax fasciatus — Castro et al. 2004: 32, fig. 4a, 5. Astyanax aff. fasciatus — Graça and Pavanelli 2007: 54, 57; Bifi et al. 2017: 4, 5, fig. 2.5 Astyanax fasciatus — Hoffmann et al. 2015: 4, fig. A1.G. Material examined. Table 2; Figure 5C. Elongated body; terminal mouth; inner row of premaxilla with 5 teeth, outer with 4 or 5, dentary with 10–12, and maxilla with one tooth. Complete lateral line with 34–36 pored scales; transversal series above lateral line with 5 or 5½ scale rows and below with 5 scale rows. Dorsal fin with 11, pectoral fin with 15, pelvic fin with 9, anal fin with 24–28, and caudal fin with 19, total rays. Ground color silvery; dark vertically elongated humeral blotch; silvery longitudinal band on the flank (dark in fixed specimens) from humeral blotch to median caudal-fin rays, being larger on caudal peduncle and forming ovalshaped, horizontally elongated blotch. Reddish unpaired fins reddish and hyaline paired fins., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on pages 368-369, DOI: 10.15560/14.2.363, {"references":["Cuvier G (1819) Sur les poissons du sous-genre Hydrocyon, sur deux nouvelles especes de Chalceus, sur trois nouvelles especes du Serrasalmes, et sur l'Argentina glossodonta de Forskahl, qui est l' Albula gonorhynchus de Bloch. Memoires du Museum National d'Histoire Naturelle 5: 351 - 379.","Castro RMC, Casatti L., Santos HF, Melo ALA, Martins LSF, Ferreira KM, Gibran FZ, Benine RC, Carvalho M, Ribeiro AC, Abreu TX, Bockmann FA, Pelicao GZ, Stopiglia R, Langeani F (2004) Estrutura e composicao da ictiofauna de riachos da bacia do rio Grande no estado de Sao Paulo, sudeste do Brasil. Biota Neotropica 3: 1 - 39. http: // doi. org / b 2 sg","Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp.","Bifi AG, Dias AC, Frota A (2017) Fish species (Osteichthyes: Acti- nopterygii) from two tributaries of the Rio do Peixe basin, Tupa municipality, Sao Paulo state, Brazil. Check List 13: 2063. https: // doi. org / 10.15560 / 13.2.2063","Hoffmann AC, Nascimento RHC, Shibatta OA (2015) Fish fauna from tributaries throughout the Tibagi river basin, upper Parana, basin, Brazil. Check List 11: 1815. https: // doi. org / 10.15560 / 11.6.1815"]}

Characidium gomesi Travassos, 1956 Characidium gomesi Travassos 1956: 3, fig. 1 [original description]— Hoffmann et al. 2015: 4, fig. A2.F. Material examined. Table 2; Figure 5M. Elongated body; terminal mouth; premaxilla with 6 or 7, dentary with 8–10 and maxilla with no teeth. Isthmus without scales. Lateral line with 34 or 35 pored scales; transversal series above lateral line with 4 scale rows and below with 2 or 2½ scale rows. Dorsal fin with 11, pectoral fin with 11–13, pelvic fin and anal fin with 8 or 9, and caudal fin with 18, total rays. Ground color brown; 3 dark brown longitudinal stripes on dorsal region of body; dark brown stripe from tip of snout to orbit; dark brown longitudinal stripe on flank, from humeral spot caudal peduncle; dark brown transversal bars on flank, conspicuous on caudal peduncle; dark brown spot at base of median caudal-fin rays. Hyaline fins; dorsal fin with 2 dark brown oblique stripes; adipose fin with distal portion darkened; posterior half of pectoral, pelvic and anal-fin rays darkened; caudal fin with 2 dark-brown transversal bars., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on page 370, DOI: 10.15560/14.2.363, {"references":["Travassos H (1956) Ictiofauna de Pirassununga. II. Sobre Characidiinae H. Travassos, 1952 (Cypriniformes - Characoidei). Boletim do Museu Nacional do Rio de Janeiro, Zoologia, Nova Serie 135: 1 - 14.","Hoffmann AC, Nascimento RHC, Shibatta OA (2015) Fish fauna from tributaries throughout the Tibagi river basin, upper Parana, basin, Brazil. Check List 11: 1815. https: // doi. org / 10.15560 / 11.6.1815"]}

Family Auchenipteridae Trachelyopterus galeatus (Linnaeus, 1766) Parauchenipterus galeatus — Graça and Pavanelli 2007: 175. Trachelyopterus galeatus — Costa et al. 2017: 44, fig. 2C. Material examined. Table 2 Deep body; terminal mouth terminal with dentigerous tooth plates in both premaxilla and dentary. Dorsal fin with I,6, pectoral fin with I,7, pelvic fin with 7 or 8 and anal fin with 21–24, total rays. Adipose fin present. Ground color pale yellow to orange with several darkbrown irregular blotches as well as fins., Published as part of Batista-Silva, Valéria Flávia, Frota, Augusto, Kashiwaqui, Elaine Antoniassi Luiz, Abelha, Milza Celi Fedatto, Bailly, Dayani, Gubiani, Éder André & Júnio da Graça, Weferson, 2018, Ichthyofauna from three streams of the lower Iguatemi River in the upper Paraná river basin, Brazil, pp. 363-378 in Check List 14 (2) on page 373, DOI: 10.15560/14.2.363, {"references":["Graca WJ, Pavanelli CS (2007). Peixes da planicie de inundacao do alto rio Parana e areas adjacentes. EDUEM, Maringa, 241 pp.","Costa, NKR, Paiva REC, Silva MJ, Ramos TPA, Lima SMQ (2017) Ichthyofauna of Ceara-Mirim River basin, Rio Grande do Norte state, northeastern Brazil. ZooKeys 715: 39 - 51. https: // doi. org / 10.3897 / zookeys. 715.13865"]}

AIM: In this paper we assessed the effects of flooding (low and high water period) on the feeding activity and diet composition of Serrapinus notomelas in patches of the macrophyte Eichhornia azurea in a shallow floodplain lake (upper Paraná River Floodplain, Brazil). We also assessed the variations of diet composition and feeding activity along the diel cycle. METHODS: Traps were used to catch the fish inside of macrophyte patches monthly from June/2007 to May/2008. A total of 1038 stomachs were examined. We assessed the feeding activity with the mean stomach fullness degree method. To summarize and support the results of diet composition in the different periods (low and high water periods) and times (dawn, light period, and dusk), was applied a nonmetric multidimensional scaling (NMS). RESULTS: The feeding activity of S. notomelas did not differ between low and high water periods, but it differed along the diel cycle. The feeding activity was higher during the light period and dusk, at both the low and high water period. The diet composition differed significantly between low and high water periods, and also along the diel cycle. In the low water the diet of S. notomelas was composed mainly by algae and in the high water by Cladocera. Algae were consumed mainly during the light period while Cladocera in dawn and dusk. CONCLUSIONS: Our results indicate that the oscillations in the water level affect the diet composition, but not the feeding activity of S. notomelas. These seasonal changes are probably related to the temporal abundance of food resources, thus, when Cladocera density was low (low water), S. notomelas consumed mainly algae but when Cladocera was more abundant (high water), it became a common food resource. OBJETIVO: Neste estudo nós avaliamos os efeitos do regime hidrológico (seca e cheia) e do ciclo diário (horários) na atividade alimentar e na composição da dieta de Serrapinus notomelas em bancos de Eichhornia azurea em um ambiente raso da planície de inundação do alto rio Paraná, Brasil. MÉTODOS: Os peixes foram amostrados mensalmente, entre junho/2007 e maio/2008, com armadilhas colocadas dentro dos bancos de macrófitas. Foram examinados 1038 estômagos. A atividade alimentar foi avaliada através do grau de enchimento médio dos estômagos. Para sumarizar e interpretar os resultados da composição da dieta por período (seca e cheia) e ciclo diário (horários) foi aplicada uma NMS. RESULTADOS: A atividade alimentar de S. notomelas não diferiu significativamente entre os períodos de seca e cheia, mas foi significativamente diferente durante o ciclo diário. A atividade alimentar foi mais intensa no período diurno e ao entardecer tanto na seca quanto na cheia. Diferenças significativas na composição da dieta foram verificadas, entre os períodos de seca e cheia, e entre os horários do dia. Na seca, a dieta de S. notomelas foi composta principalmente por algas e na cheia por Cladocera. As algas foram consumidas mais intensamente no período diurno e Cladocera ao amanhecer e ao entardecer. CONCLUSÕES: Nossos resultados indicam que o regime hidrológico afeta a composição da dieta de S. notomelas, mas não afeta a atividade alimentar. As variações sazonais na composição da dieta provavelmente estão associadas às variações temporais na abundância dos recursos alimentares regidas pelo regime hidrológico. Assim, quando a densidade de Cladocera foi baixa (seca), S. notomelas consumiu predominantemente algas, mas quando Cladocera foi abundante (cheia) passou a ser um recurso alimentar importante para S. notomelas.