Lesser-known British Freshwater Fish Quiz

Answer: Bitterling

The bitterling (Rhodeus amarus) is a pond and aquarium fish native to Central Europe that has become established in some British lakes and canals.
It is small, only 2-3 inches long, silver in colour, and remarkable for its use of an ovipositor in breeding. The ovipositor is a tubular extension that the females develop when breeding and use to lay their eggs securely in freshwater mussels.

Answer: Ruffe

Ruffe (Gymnocephalus cernua) are members of the perch family and like perch, have sharp, spiny fins and gill covers which they use as a form of protection.
Ruffe are small fish (they can grow to 10-11 inches long, but are rarely more than 6-8 inches long) but have large mouths and feed on small insects and larvae, and fish eggs and fry.
They are widespread in throughout Europe and Asia as well as England and Wales, and have been introduced to the North American Great Lakes, where they are regarded as an invasive nuisance.

Answer: Gudgeon

Gudgeon (Gobio gobio) are bottom feeders that find their food, mostly bloodworm, with the aid of two barbules at the sides of their mouth. They differ from barbel which have four barbules and are much smaller, typically only four to six inches long.
Gudgeon are widespread, but with a preference for slow-moving water and canals.

Answer: Rudd

Rudd (Sardinius erythropthalmus) develop bright red fins as they mature, and live in still or slow-moving water, where they are primarily surface feeders. Because of this, they have upturned mouths, and their dorsal fin is set slightly further back than roach. Nevertheless the two are often confused and the distinction is blurred further as they often interbreed.
Both rudd and roach are members of the carp family and can grow up to about four pounds, although a two-pound fish is exceptional in both cases.
Rudd are more common in the south of England.

Answer: Flounder

Flounders (Platichthys flesus) are sea fish that are found in most estuaries, but they are capable of travelling considerable many miles up rivers, especially where rivers are tidal.
Like most true flatfish, they start off with an eye on either side of the body like most other fish, but as they grow, the eyes migrate to one side and the flounder continues life on its side.
Flounders can grow up to five or six pounds, but most weigh less than two pounds.

Answer: Lamprey

There are three British species of Lampreys. The brook lamprey (Lampetra planeri) is the smallest, typically 4-6 inches long, and feeds on algae. The river lamprey (Lampetra fluviatilis) is larger, typically 12-18 inches at maturity. River lamprey are migratory, spending their adult life at sea and returning up-river to spawn. Sea lamprey (Petromyzon marinus) are larger still, reaching 20-40 inches in length; they too are migratory, growing up-river before spending their adult life at sea, and returning to spawn.
All the lampreys are eel-like in shape, and cartilaginous, with skeletons of cartilage rather than bone, like shark and rays. Unlike shark and rays, they lack a jaw, and instead have a round, toothed, sucker-like mouth which the river and sea lampreys use to feed parasitically on other fish. The brook lamprey doesn't feed in its adult stage, but lives off reserves stored up before maturity.
Lampreys have been prized as a food fish in the past. King Henry I of England was famously said to have died from eating "a surfeit of lampreys".

Answer: Zander

Zander (Stizostedion lucioperca) are a European species that is non-native to Britain, which has become established in many waters. They were introduced legally into several fisheries, and illegally into the canal system, where they have spread.
Zander are apex predators that can grow up to 20 pounds. They are related to, and have similar features to perch, but with the shape and behaviour of pike. Because of this, they have been wrongly though to be a hybrid, as reflected in their Latin name, 'lucioperca'.
Zander are a highly regarded food fish in mainland Europe.

Answer: Vendace

The Vendace (Coregonus albula) is a species of freshwater whitefish, native in the UK only to Bassenthwaite and Derwentwater in the English Lake District.
Whitefish are a widespread northern species globally, and often a popular food fish, but the British population was isolated following the last Ice Age, and is consequently very rare.
Closely related is the powan or gwyniad, classified as Coregonus lavaretus, but which may be the same species. Powan or gwyniad are found in a very few upland waters in Scotland and Wales as well as the Lake District.
Vendace look not unlike herring, and require deep, cool water with plenty of oxygen, where they normally feed on small insects and larvae, and smaller fish.

Answer: Wels catfish

Wels catfish (Silurus glanis) are capable growing to very large sizes. In warmer waters elsewhere in Europe they have been known to exceed 600 pounds. Introduced to some waters in south-east England, the largest known have reached only 100 pounds, but even this makes them largest freshwater fish species in the UK.
Named catfish for their barbules surrounding their mouths, they combine the use of these with a keen sense of smell and some night vision to detect their prey. While their diet is usually fish, wels catfish have also been known to take small animals and birds.
Due to their predatory nature and size, there are occasional reports of wels catfish attacking humans.

Answer: Burbot

Burbot (Lota lota) occur widely throughout the colder waters of the Northern Hemisphere, but the last recorded occurrence in the UK was in 1969. Burbot used to be commonplace in eastern England and Maskell's "Booke of Fishing with Hooke and Line" (1590) describes their preference for colder conditions: "they stirre not all the sommer but in winter when it is most coldest weather".
The name 'burbot' derives from the Latin 'barba', meaning beard, and this refers to the single barbel that the burbot has under its chin (like the cod). In some respects, burbot resemble ling, having a long body with dorsal and anal fins that run half the body's length.
Burbot are predators with extensive tastes, preying on smaller fish, and also amphibians and occasionally birds.