Greenpeace

Iridescence (also known as goniochromism) is generally known as the property of certain surfaces which appear to change colour as the angle of view changes. Iridescence is commonly seen in items such as soap bubbles, butterfly wings, and sea shells.

Although the vast majority of seawater has a salinity of between 3.1% and 3.8%, seawater is not uniformly saline throughout the world. Where mixing occurs with fresh water runoff from river mouths or near melting glaciers, seawater can be substantially less saline. The most saline open sea is the Red Sea, where high rates of evaporation, low precipitation and river inflow, and confined circulation result in unusually salty water. The salinity in isolated bodies of water (for example, the Dead Sea) can be considerably greater still.  Louis J. Sheehan, Esquire

There are two dorsal fins, the first one spiny and the second soft. There is also an anal fin, which is also considered spiny, and a caudal fin. The cloaca lies directly behind the anal fin. All perciform fish share the perch's general morphology.

The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually