Goldfish are easy to care for, providing endless entertainment through cliches, jokes, fraternity hazing rituals, cliches and memes. Yet their popularity does not mask their threat to natural habitats - goldfish can spread disease to local ecosystems.
Goldfish possess long dorsal and anal fins, with a saw-toothed spine on their front fins, short jaws, and round bodies.
They are a member of the Cyprinidae family
Goldfish belong to the Cyprinidae family of fishes, which encompasses numerous varieties. Domestic goldfish evolved from dark-gray carp native to East Asia. Hybridization between this type and Koi and common carp occurs commonly.
After their domestication over 1,000 years ago in China, goldfish have since evolved into ornamental breeds suitable for aquariums and ponds. Different colors and sizes can be bred; some even grow larger than their wild cousins!
Goldfish are commonly misidentified as "carp," however they belong to the Carassius genus of Cyprinidae fishes and should be called Cyprinids instead. Goldfish belong to Carassius' Carassius subgenus in order Cyprinidae family with heavy bodies with forked tails and large scales; their dorsal fin possesses over 15 main rays with no barbels (Page and Burr 1991; Murdy et al. 1997); their anal fin has six rays with its first usually being spine-like (Page and Burr 1991; Murdy et al. 1997).
They are a member of the Nishikigoi family
Goldfish are popular pets kept as aquarium inhabitants or pond dwellers, although they can also be found wild in rivers and lakes. Goldfish belong to the order Cyprinidae and can reach quite large sizes; their scales include matt, metallic, and nacreous varieties; their typical coloring ranges between greenish brown or gray and other hues due to selective breeding programs that have resulted in many variants being bred selectively for aesthetic reasons.
Goldfish differs from koi in that it's an entirely separate species bred through artificial selection to become decorative fish, becoming known as nishikigoi due to their likeness of multicolored patterns on Japanese kimonos.
Nishikigoi goldfish species is distinguished by light blue above their lateral line and red or orange below, often sporting yellow spots on their cheeks. Shusui, the most sought-after variety among this breed of goldfish, features pale greenish-blue spring onion color with one line of large mirror scales running dorsally from head to tail.
They are a member of the Asian carp family
Goldfish belong to the Asian carp family and are closely related to crucian carp. Goldfish are bottom feeders that consume both plants and animals by using their pharyngeal teeth for crushing food particles, and highly resistant to fluctuating temperature conditions in their aquatic environments. Common habitats for goldfish include ponds or streams with submerged vegetation.
Goldfish have been selectively bred to be smaller than carp, enabling them to fit comfortably into smaller tanks. Furthermore, their breeding process is much simpler and they adapt more readily to captivity than their carp counterparts; making goldfish ideal pets for those without large ponds.
Pet owners frequently compare goldfish and Koi because their sizes and colors are comparable, though Koi have more fins and tail fins compared to goldfish, and typically tolerate humans more readily than their goldfish counterparts. Still, distinguishing Koi from Goldfish can sometimes be challenging; some varieties such as Shubunkins and Comets bear body shapes that resemble those of Kois while still remaining smaller in size than Kois.
They are a member of the Prussian carp family
Goldfish are bottom feeders, using their pharyngeal teeth to crush food into pieces for digestion. Found across freshwater habitats and highly adaptable, goldfish thrive even during periods of fluctuating water conditions or temperature changes while being highly resistant to low levels of dissolved oxygen in the environment. With such characteristics making goldfish one of the most successful invasive species found across Europe.
Gold fish, Cyprinus carpio species, can be distinguished from other common carp by their distinctive colors and fins. Gold fish also possess various scale colors including matt, metallic and nacreous; matt scales have a dull finish while metallic scales boast larger dimensions with shiny surfaces while Nacreous scales come with pearly finishes for an added pearly touch.
The GLMM model indicates that an increase in Prussian carp abundance correlates with a reduction in native fish community composition, perhaps as a direct result of its impact on benthic invertebrate communities that serve as food sources for most native species in their food webs.