Morphotype‐dependent feeding responses in the guppy Poecilia reticulata Peters, 1859 (Class: Actinopterygii) fed zooplankton

Abstract

Many aquarium fish species have diverse morphotypes. Since different morphotypes may have different preferences for various prey items, offering a single prey species is inadequate for successful aquaculture. Poecilia reticulata, a popular aquarium species, occurs in different morphotypes. To test whether the four morphotypes (yellow tail YT, red tail RT, metallic blue tail MBT and black tail BT) of this fish prefer different items, we quantified somatic growth, feeding behaviour, zooplankton selectivity and functional responses. Standard length (4.5 vs. 11.7 mm) and gape size (0.37 vs. 0.91 mm) of four morphotypes increased linearly with larval age; YT and RT had 25% longer body length and larger gape than the others. Prey encounters, attacks, captures and ingestions increased with larval age. Lowest ingestion rates were recorded for the RT morphotype on rotifers. At any given larval age, prey consumption increased with increasing prey availability. During the fourth and fifth weeks, larval YT and RT consumed higher number (37 ± 1 ind./predator/30 min) of cladocerans compared with other two morphotypes (24 ± 1 ind./predator/30 min). Prey selectivity data showed that larvae of MBT and BT continued to prefer rotifers up to 4 weeks, while those of YT and RT preferred cladocerans during the 4th week.