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Ancestor: Oncorhynchus mykiss irideus (Rainbow Trout)

Descendants: Riversnare Trouts

Size: Up to 1m

Dietary Needs: Generalist predator, eats any animal it's large enough to catch. Hatchlings eat tiny water invertebrates. Over time they move on to fish (including young of their own species) and crayfish. They also start ambushing small animals like mice and birds from the water's edge where the water is deep enough next to the river bank. Due to being cold-blooded water breathers they can lie in wait motionless for a long time without expending much energy. As they grow larger their bodies demand larger reward for the effort of hunting, so they start eating their same-species adult competitors, rabbits and cats that enter the water or try to drink from it.

Life Cycle: This genus of fish does not live in salt water, as it never smolts. Instead of moving out of the river system seasonally it avoids brackish water and competes for freshwater space more aggressively.

Their ancestors used to swim upstream to their spawning grounds and then die from the effort with few exceptions. This is still somewhat true, but a fish can usually get a few years of spawning before a spawning season will finally take them. There is some population variation between fish that put all of their life energy into one spawning season (male turns red almost all over before it dies), and those that retreat from the event to recover for the next year when they feel exhaustion (male appears flushed along the lateral line, but overall stays a normal colour). The former does better during years of sparsity followed by a year of plenty, while the latter does better during years of plenty followed by sparsity of food so the variations have never been lost in most species.

When congregating in the upstream spawning grounds there is some competition between the trout in the form of side-by-side sizing up, but desparate males will also home in on active spawning when a victorious male initiates the spawning from the female and try to get their own sperm in. As some of the fish are dying, the process is pretty chaotic. Females produce at least 10,000 eggs each in one season, the larger the female the more she produces. Most of these eggs will get eaten, destroyed by the environment, will succumb to disease and so-on but by sheer numbers a few will make it back to the spawning ground as mature adults.

Females usually live slightly longer than males, sometimes over 10 years. Males usually don't live past 5.

Other: As the adults grow larger (over a year) their heads become flatter and tilt upwards, priming them to see up through the water in front of them as more of their prey is terrestrial at larger sizes. The spine also has some limited flexibility to switch between upwards looking and forwards looking, but this switch is very slight.