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Lactase persistence or lactose tolerance is the continued activity of the lactase enzyme in adulthood, allowing the digestion of lactose in milk.In most mammals, the activity of the enzyme is dramatically reduced after weaning. [1]
The following is a list of aquarium diseases. Aquarium fish are often susceptible to numerous diseases, due to the artificially limited and concentrated environment. New fish can sometimes introduce diseases to aquaria, and these can be difficult to diagnose and treat. Most fish diseases are also aggravated when the fish is stressed.
The majority of humans actually follow this protocol as well, and down-regulate lactase production around 3-5 years of age. Interestingly, though, the majority of caucasians, mainly those from northern european background, continue to have elevated lactase activity all the way into adulthood, and so they exhibit “lactase persistence”.
Unlike mammals, the red blood cells of fish have DNA, and can become infected with viruses. The fish develop pale gills, and may swim close to the water surface, gulping for air. However, the disease can also develop without the fish showing any external signs of illness, the fish maintain a normal appetite, and then they suddenly die.
This category is dedicated to the various Fish diseases. For an overview of this subject go to Fish diseases. Subcategories.
Fishes are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal taxonomy.Traditional classification divides fish into three extant classes (Agnatha, Chondrichthyes, and Osteichthyes), and with extinct forms sometimes classified within those groups, sometimes as their own classes: [1]
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The infected fish also becomes lethargic, swims near the surface, and its appetite decreases. [10] Additionally the infected fish may hold its gill covers open and scratch its gills on rocks. [14] In severe infections, Dactylogyrus species can cause hemorrhaging and metaplasia of the gills which can lead to secondary bacterial infections and ...