10 20 40 60 cm
mittakaava > 60 cm
New York State Department of Environmental Conservation, Jouko Lehmuskallio, Lauri Urho
Oncorhynchus mykiss (Walbaum)
- Family: Salmonids – Salmonidae
- Similar species: atlantic salmon, brown trout
- Size: 40-70 cm, 1-5 kg.
- Appearance: Head smaller than the salmon and brown trout, snout noticeably more rounded. Body also deeper than salmon and brown trout. For a fish related to the Pacific salmon, the rainbow trout’s anal fin is fairly short (8-12 rays).
- Colouring: Liberally sprinkled with small black spots covering back, sides and head as well as dorsal, adipose and anal fins. Back dark grey, sides silvery and belly pale. Highly distinctive of the rainbow trout is the pink to pale violet band extending along either side of the lateral line to the tail.
- Reproduction: Spawns in spring on gravel beds in flowing water. Not known to reproduce regularly in Finland, where all rainbow trout have been planted or have escaped from fish farms.
- Food: Insect larvae, surface insects, crustaceans and small fish.
- Distribution and habitat: Most stocking with rainbow trout today is with catchable size fish intended for rod-and-line fishermen. Some escape from ponds and cages at fish farms. Most people will have seen rainbow trout on their local supermarket’s fish counter. Rainbow trout are not as demanding as Finland’s other salmonids in terms of water quality, hence their popularity in aquaculture, although they fail to reproduce in waters that are too acidic.