Most species of trout do have teeth, although depending on the species the teeth may be located in different places. For example, rainbow trout have a mouth that doesn’t go past the back of their eyes and teeth that are located along the roof of their mouth whereas other species of trout have teeth that are located along the base of their tongue (known as hyoid teeth).

When some trout are feeding they often engulf their prey. Sometimes they may follow their moving prey very slowly or their prey may be carried by the current in front of a trout which has happened to open its mouth. When this happens the trout’s gills flare up and the prey is sucked into the fish’s mouth. Here, the prey is then trapped by the tongue against the roof of the mouth as a means to “test” the food and it is then either swallowed or expelled. This process is done very quickly.

To engulf some prey would pose a deadly threat to these fish. For instance, the Freshwater crayfish is equipped with spikes and a spine that would catch in the throat of a trout and result in choking the fish. It is for this reason that the crayfish must be grasped and turned tail first toward the throat and then swallowed. This grasping feeding system is done by the trout using its small, sharp grasping teeth.

It is true that trout is a fish that is typically considered to be kosher. The literal translation of the word kosher is ‘fit’. The tern Kosher is primarily used when referencing to food that has been prepared and eaten according to ‘kashrut’ or Jewish dietary laws. In order for something to be considered kosher the basic rules have to be applied:

• Fish must have scales and fins and must come from a kosher species.
• If a packaging that the fish is in has the kosher certification it doesn’t necessarily have to have the skin on it, although it does make verification easier.
• Land animals must have split hooves and chew their cud.
• Birds cannot be amongst the foods that are listed forbidden in the Torah and cannot be hunters/scavengers.
• Animals are required to be killed in a specific manner and must be free of all disease
• Any type of meat and/or poultry must be certified kosher.
• Meat and dairy are not to be combined in any way. (poultry is considered meat as well in this case). Products that contain dairy byproducts cannot be combined with meat either.
• Fish and/or meat cannot be served on the same dish or at the same time.
• Some groups consider milk to be acceptable but some groups will still require a kosher certification for the milk.
• Some groups do not eat certain vegetables because they consider them to be too unsanitary and hard to clean bugs and debris off of.
• Any processed ingredient must have kosher certification
• Some groups require that a jew be involved in the food preparation when cooking food.

The following trouts and whitefish are considered to be kosher: Atlantic salmon, Pacific salmon, coho salmon, silver salmon, sockeye salmon, blueback salmon, red salmon, Chinook, king salmon, spring salmon, pink salmon, humpback salmon, chum salmon, dog salmon, fall salmon, brown trout, rainbow trout (a.k.a. steelhead), cutthroat trout, golden trout, lake trout, brook trout, Chars, Arctic char, dolly varden, whitefish, ciscos, lake herring, chubs and graylings.

It is also highly recommended that individuals concerned with their trout being kosher to only purchase fish from a reliable kosher fish store, only fish with a skin still intact that can be properly identified. Especially since the FDA has even admitted that species substation is a series problem that commonly occurs.

It is a myth that trout are colorblind. In fact, many shallow water fish of both oceanic and fresh water systems such as the trout or salmon have well defined color vision and can even see colors that we humans are not capable of seeing. The trout’s vision traits evolved as it did in other animals as a mechanism to allow them to better separate potential food items from the background. For example, in a watery habitat the background may be located at the bottom of the water which is normally a tarnished olive to green color or the background could even be the water itself. When looking horizontally through clear water, the background appears to the trout as a pale, silvery blue color. This phenomenon is known as background space light and is caused by the scattering of blue light as it passes through the water. In water with a lot of suspended algae, the background space light is typically found to be a greenish yellow color whereas in bog water, the background space is more likely to appear a reddish brown color.

One of the reasons many fishermen use flies or lures with strong coloration is to make them stand out more against the background space light and attract fish. The red and yellow fish lures and flies are quite popular among many fishermen today for this reason. Fluorescent colors are also quite popular as they stand out stronger than most lures and flies and have highly fluorescent shades that are very attractive to salmon and trout in the area making them much more likely to bite.

Trout can distinguish colors with ease and do not usually discriminate between very fine shades of any color for selective feeding purposes, rather they may discriminate between four or five shades of color varying from the palest shade to the darkest when feeding. The reason for their lack of color hyper-sensitivity is that since their food organisms vary slightly in color, if the trout were too sensitive to color much of the food would get away.

Interestingly enough, It has also been found that those shades of color consisting of more chroma ( meaning it appears to be more intense than the color of the natural) are more attractive to selective trout. Along with being able to better find food this way, the fact that trout see further into the ultraviolet range than humans do (they see colors that are not visible to us), could be another reason for why they are more attracted to the colors with more chroma. This also means that the watery environment the trout reside in could be influencing the transmission of specific colors. In addition to this, skylight varies during the day. In morning and evening it contains more red resulting in reds, oranges and browns standing out more during this time.

The rods and cones in a trout’s eyes physically swap places at both the start and end of daylight. In the evening, the cones which give rise to color response but need high light levels to operate are withdrawn into the surface of the retina and the rods obtrude. At dawn this action is reversed. How the trout’s brain assesses the combined cone response and what the fish experiences as a result of this response is still something that scientists are trying to figure out. However, it is definitely clear that fish such as the trout possess the mechanism for full color vision as we humans know it, and with somewhat a higher range than what we can even comprehend.

Trout are indeed capable of swimming upstream. Biologically speaking, most trout swim upstream in response to sex hormones when it is time for them to spawn. This causes them to first seek highly oxygenated water to fight the current. There is also a fairly complicated evolutionary history behind the trait of trout swimming upstream. This fish initially started out as a freshwater fish. However, as time went on their ancestors moved into brackish rivers and finally into oceans. Because they evolved in freshwater, the eggs could still only survive in fresh water. As a result every year the trout ancestors were required to move from the ocean back into the freshwater when it was time to reproduce.

However as trout moved through the oceans they gradually began to discover new rivers and streams located in new countries, as well as streams that had just formed on their own with time. The trout began to breed in these new streams and some of them never moved back to the oceans. As a result today there are a lot of different types of trout and while most do still move back to the oceans after they hatch, some live their entire lives in freshwater environments. Some species of trout such as the Steelhead are able to do either, with some individuals returning to the oceans while others starve in the freshwater where they are born.

Because all trout ancestors evolved to swim from the ocean back up the freshwater streams, most species of trout can still be found doing so today. Even those trout that have never left the freshwater begin to feel the urge to move and swim higher upstream. Some trout species never swim upstream, and instead opt for clean water which many times is located downstream.

It is true that trout and salmon are related. In fact, they are so closely related that fishermen and scientists often have a difficult time classifying the individual species. Both fish are classified as “an oily fish”. Technically Trout are a species of freshwater and saltwater fish and Salmon belong to some of the same family as trout. However unlike most trout, most salmon species spend most of their lives in salt water and are not usually found in fresh water on a regular basis.

In 1989 DNA tests showed that the rainbow trout also known as the steelhead really isn’t a trout at all, and the fish was reclassified as a salmon. Likewise, the Atlantic salmon was then not determined to be a salmon after all, and reclassified as a trout.

The salmon and trout family is quite large and also includes great game fish such as the trout, salmon, chars, and grayling. It also includes baitfish such as the whitefish and ciscoes. This family is native to cool/cold streams and lakes throughout Europe, Northern Asia and North America and has also been known to reach as far south as Northwest Mexico and Northern Africa.

Some of the main species of salmon include the following:

• Adriatic trout
• Atlantic trout
• Brown trout
• Cutthroat trout
• Flathead trout
• Hucan salmon
• Kokanee salmon
• Land-locked trout
• Maramorta trout
• Ohrid trout
• Pacific salmon
• Rainbow trout
• Sevan trout
• Steelhead salmon