Topmouth Gudgeon Care Guide
Pseudorasbora parva is a hardy East Asian cyprinid, listed as an invasive alien species of concern in the EU.
Compiled by Aquairi from published sources · Published · Updated
Overview
Pseudorasbora parva, the topmouth gudgeon or stone moroko, is a small cyprinid native to East Asia. According to FishBase and Wikipedia it is a hardy species with a superior (upturned) mouth that has become widely invasive outside its native range. It is rarely kept in the ornamental trade because of its invasive potential.
Taxonomy
- Family: Gobionidae (formerly placed in Cyprinidae)
- Genus: Pseudorasbora
- Scientific name: Pseudorasbora parva (Temminck & Schlegel, 1846)
- Common name: Stone moroko (FishBase)
Habitat
FishBase records the native range from the Amur to the Zhujiang (Pearl River) drainages across Siberia, Korea and China. Wikipedia adds Far East Russia and Taiwan. It is a freshwater, benthopelagic fish of temperate waters that has been introduced and become invasive across Europe and parts of Asia.
Tank requirements
- Minimum tank volume: 100 L (about 26 gal)
- Temperature: 4-24 °C (39-75 °F)
- pH: 6.5-8.0
- GH: 8-20 °dGH
- School size: at least 6 individuals
- Maximum length: about 12.5 cm TL (FishBase)
- Lifespan: 4-6 years
Diet
The species is an omnivore (FishBase trophic level 3.1). FishBase reports it feeds on small insects, fish and fish eggs as well as plant material. Predation on the eggs of native fishes is one reason it is regarded as an ecological pest.
Compatibility
The topmouth gudgeon is peaceful and shoaling, occupying the middle water column, and is plant-safe. It is cold-tolerant and suits unheated tanks with species such as White Cloud Mountain minnows; it should not be mixed with strictly tropical fish or kept with delicate small fish whose eggs it may eat.
Breeding
FishBase reports it breeds in still or slow-flowing water, with females spawning three to four times in a season and males guarding the eggs until they hatch. Its high reproductive rate contributes to its invasiveness.
Conservation status
IUCN Red List: Least Concern (assessed 2020). Wikipedia notes that since 2016 it appears on the European Union list of Invasive Alien Species of Union concern, which prohibits its import, breeding, transport, sale and release within the EU.
Breeding Topmouth Gudgeon
Overview
The Topmouth Gudgeon (Pseudorasbora parva) is a hardy East Asian cyprinid that thrives in temperate fresh and brackish water at 5-22 degrees C. Reproduction involves male-built nests and male guarding of the eggs. Its high reproductive rate makes it a noted pest outside its native range.
Sexing
The species shows sexually dimorphic coloration in large adults, and individuals may take on different colours during the spawning season. Males clear and prepare nest cavities using specialised pearl (tubercle) organs.
Breeding Setup
Provide still or slow-flowing water with well-vegetated areas and hard surfaces such as stones, which the male uses as a nest site. The temperate temperature range of 5-22 degrees C suits an unheated, well-oxygenated tank. Sexual maturity is reached at around 3.0 cm in length.
Spawning Behavior & Trigger
The male constructs a nest under a stone, clearing the cavity, and the eggs adhere to the ceiling of the cavity. The female spawns repeatedly, three to four times per season. The male guards the eggs but leaves the nest before they hatch.
Egg & Fry Care
Eggs are guarded by the male during incubation and remain attached to the cavity ceiling until hatching. Because the male departs before hatching, the fry receive no further parental protection. Maximum reported lifespan is about five years.