Fighting behaviour in native fish: the Mexican mojarra (Cichlasoma istlanum) wins when confronted with the non-native convict cichlid fish (Amatitlania nigrofasciata)

Female preference for dominant males in the Mexican mojarra cichlid fish, Cichlasoma istlanum

“…During a contest, fish show aggressive behaviour displays such as lunges, chases and lateral displays (Archundia & Arce, 2019; Lorenz et al ., 2011). Fish could establish dominance with these behaviours rather than physical fights, allowing them to avoid the costs and risks of an actual fight.…”

“…Their sex was determined by identifying the genital papilla using methylene blue (Earley et al ., 2006). Fish were grouped by total length (TL), and mass (M) and lateral area (LA) (De La Torre et al ., 2018) which was calculated using the photographs in lateral view and analysed using Image J software (Archundia & Arce, 2019; Schneider et al ., 2012). For each trial, a Mann–Whitney test was used to match a group composed of two males of similar LA (202.21 ± 5.12 mm 2 ; W = 32.5, P = 0.19, df = 1, r = 0.29, with 95% C.I.…”

“…The water in the tank had the same physical and chemical characteristics as during the acclimation period. The sections were divided with transparent a 1 cm screen so that the fish could maintain visual and chemical perception (Archundia & Arce, 2019; Thünken et al ., 2012). Males were placed individually into the sections on the left and right sides of the tank (Raymond et al ., 2015), and the female was placed in the middle section inside a circular enclosure made of the same transparent 1 cm mesh as the section dividers.…”

Aggressive interactions and consistency of dominance hierarchies of the native and nonnative cichlid fishes of the Balsas basin

“…Cichlid fish were reared at the Laboratorio de Acuicultura e Hidrobiología, Centro de Investigaciones Biológicas, Universidad Autónoma del Estado de Morelos in separate 5 L plastic containers. For the acclimation period, 30 sexually mature males of each species were selected by observing the genital papilla (Archundia & Arce, 2019;Arnott & Elwood, 2009a;Earley et al, 2006) and were separated by species into five 180 L tanks for 30 days (30 conspecific males per tank; Desjardins et al, 2012). The physical and chemical conditions of the water were kept constant at 27°C ± 1.0°C, constant aeration (5.8 mg/ L), pH ~7 and 12-h light:12-h dark photoperiod (Archundia & Arce, 2019).…”

“…In one-on-one contests, and even when outnumbered, Mexican mojarra have demonstrated dominance over the nonnative convict cichlid (Archundia & Arce, 2019;Molina et al, 2021). However, the presence of tilapia, spotcheek cichlid, and green terror could alter this hierarchy, potentially making the Mexican mojarra subordinate when all four nonnative cichlids are present.…”