Observaciones de grubio

Probably the same as in 11490354 by @hanajos,

Mallard is in 13168076,
Nutria is in 13168075.

Actively explored the area in bright sunlight at ~2 m depth, no evidence of its den. Changed colour and texture quickly, also sent waves of of lighter colour running over its body to imitate reflexes of sunlight caused by the waves; all images of same individual.

Mute Swan (first image) is in 13309129 (probably the same as in 11490354 by @hanajos),
Mallard is in 13168076.