The sudden transfer of the fishes into water more than 3 to 5* cooler is to be 

 avoided on account of resulting shock reaction. Especially when setting out brood, the 

 transportation water must previously be brought to the same temperature as the pond water. 



Bursting of trout ep.p.s . At tines, among the trout eggs shortly before hatching, are 

 to be found many ruptured eggs from v/hich v/hitish masses exude. This phenomenon is to be 

 observed especially after transportation and shortly before hatching and is due to an 

 injury and the bursting of the egg shell whereby portions of the vitellus exude and 

 coagulate. 



Gas bubbles (gas bubble disease). Observed in trout broodlings. Symptoms: Gas 

 bubbles under the skin, especially around the head and along the fins. According to 

 Plehn . it is due to an over-supply of oxygen (all to plentiful vegetation). Hrsic has 

 shown that at temperatures of 1.4''C. and over, this affliction will occur even without 

 oxygen super-saturation, especially in narrow storage containers. 



Accumulation of egg shells in the abdominal cavity . Over-aged three year and older 

 masted female trout perish easily, because the shells of unlaid eggs of previous years 

 fill the abdominal cavity. Then there is a lack of space for the development of new eggs. 

 The fishes, according to experience, thereby become feeble. For this reason the over- 

 aging of the masted female trout is to be avoided. 



Inflammation- of stomach and intestines . Both diseases are caused through unsuitable 

 foodstuffs. They are among the most frequent trout diseases and will cause great losses. 



Inflammation of the stomach, leading to a reddening of the mucous membranes of the 

 stomach lining, is due to a too high salt content of the food (see Chapter VII). 



Inflammation of the bovrels , SjTiptoms: Hyperemia of the intestinal blood vessels, 

 intensive reddening of the rectum. (T!ic-se s^Tiiptoms are not characteristic for the 

 disease in dead fish, since reddening of the intestinal tract is usually always observed 

 in dead fish.) The bowels are full of a yellov.'ish mucus, there is a reddened vent, and 

 prolapsus occurs quite frequently. In chronic cases, the mucous membrane may be notice- 

 ably darkened and in ver\' severe cases the trout execute violent sv.'Lm. movement s , nay even 

 be seen jumping about. 



Cause: In the majority of cases spoiled food, also indigestible food or food hard 

 to digest, such as too much fat altogether, too much protein, overfeeding, etc., may lead 

 to inflammation of the bov/els. Aside from this, certain infections and parasites laay be 

 responsible. These causes will be discussed later on. It is of interest that even a 

 natural diet (too fatty chironomus larvae from sewage water, for instance) may brin~ 

 about intestinal disorders and inflammation of the rectum ( Miegel ). It is characteristic 

 that these inflammations, accompanied b;^ great losses occur mostl;/ during the first warm 

 summer days. The accompanying chart, Fig. 6/t, shows that within two days the losses 

 increase greatly and then slowly decrease within about six days. 



The only remedy lies in an immediate cessation of feeding for about 1/+ days, that is, 

 until losses stop completely, \1hen feeding is taken up again, only the best available 

 and best suited food is to be given, 



Lipoidal degeneration of the liver . This disease occurs ir trout only and especir.lly 

 in chronic form among older fish. Cause: Faulty diet, such as lack of variety of food 

 combined v/ith lack of vitamines; may also be caused 'oy over-feeding at, low temperatures. 

 Symptons: Yellowish-grey or quince-j'ellowish, often spotted liver. The -tallbladder is 

 frequently clear and colorless, the fish are anemic, feeble and occasionally of -Jarkish 

 color. A gradual recovery can be attained by proper diet, to ivit: not too concentrated 

 food, frequent changes of food mixtures rich in vitamines. 



Fatty degeneration of the liver . Occurs among carp-like fish, especially a;nong 

 "displaj"" fish, kept in garden ponds, for instance and strongly f e I with br'ead. Over- 

 feeding of older fish will also cc.use the affliction. 



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