This section is from the book "The Goldfish And Its Systematic Culture With A View To Profit", by Hugo Mulertt. Also available from Amazon: The goldfish and its systematic culture.
The name "slime" has heretofore been applied to this description of disease, but without any apparent reference to the cause producing the trouble. In the author's opinion, it is the presence of the parasites that makes the whole difficulty. They annoy the fish by their presence, their attacks upon its skin setting up an increased flow of blood to the part upon which the thick coat of slime is found. Manifestly the best method of treating the disease is the removal, or rather the prevention, of the cause, for if the bacteriae are not allowed to develop, they of course can do no harm.
Tadpoles and snails should be put into the aquarium to consume any remaining particles of food, and the feeding itself more carefully attended to. Place the aquarium in a warm and light location, adding to the water a pinch of table-salt when filling the vessel.
Dropsy, as every one knows, is a swelling up of the body, caused by the presence of watery fluid in the tissues, so it is with fish when affected in this way.
It generally begins near the tail, but sometimes about the middle of the body and progresses forward. When it first makes its appearance, a few scales in a circle around the body lose their firm attachment, at this stage, if the affected specimens are immediately removed and placed into water brought from some other locality than that in which they had been when taken ill, they will recover in a short time.
The disease having started, will, if not immediately attended to, spread over the entire body until it becomes almost spherical, so great is the distention of the skin. The scales become erect, giving the fish the appearance of a "ruffed grouse," the eyes at the same time being greatly protruded from their sockets.
During all this while the fish shows a good appetite, and continues to do so until the end, which soon follows.
No cause, as yet, has been found producing the disease; it appears upon fish in Europe, as well as in this country, and also upon fish kept in open air ponds, as well as those inhabiting the aquarium, and in any season of the year, and at any age of the goldfish.
The disease may run a course of four months, at the end of which time it results in the death of the fish. It also seems to be intermittent in character, disappearing for several weeks, and returning again upon the same individual, but always in such cases with fatal effect.
There seems to be no other treatment than making the fish as comfortable as possible, taking that chance for recovery.
This disease is indicated by what appears to be a nervous restlessness of the fish. They are seen swimming with very quick motions, darting here and there with great rapidity, and with no other apparent reason than a desire to flee from their torment, for it seems that they suffer from muscular pains. After this extreme activity which covers a period of several days, the fishes (for they all become affected at the same time) huddle together on the bottom of the tank, now and then resuming their mad capers.
The external appearance in this case is characterized by a closed dorsal fin, bloody streaks upon all of the fins, which, moreover, instead of being nicely rounded upon their extremities, as in health, become agglutinated and appear like the spikes upon a catfish. The tissue between the spines decays, the latter looking like the disarranged bristles on a brush; this is the beginning of the end.
The appetite continues in good condition, the fish, nevertheless, become lean and weaker each succeeding day until death takes place.
The cause of the disease, also, can be traced to improper methods of feeding, the stomach in consequence becoming overtaxed and the entire system disarranged.
When it does appear, all the fishes are attacked at the same time; the aquarium then should be placed where it will be exposed to the sunlight, the temperature of the locality being kept at about 700 F., and no food administered for about a month. Snails and tadpoles should not be omitted when stocking the hospital tank, as they are excellent scavengers, and by their presence will prevent a complication of diseases.
The diseases described above constitute the main ones we have to expect, and, with the exception of dropsy and tuberculosis, are easily managed, if the treatment is carried out properly.
According to the old saying, "accidents happen in the best regulated families," so will they happen to goldfish. In most cases, nature, if let alone, will repair damages with surprising skill, though a little assistance often helps to secure a desirable result. Scales that have been knocked off will be replaced, just as a finger-nail is when bruised.
Injured fins grow again, but the form afterwards does not always assume perfection.
If an eye has been torn out, it will not necessarily kill the fish, as in most cases it heals kindly, and indeed might (for appearance's sake) be replaced by an artificial substitute, such as are in use by the taxidermist.
When we wish to assist nature to heal a wound, we must bear in mind that a warm temperature is most favorable for that purpose, and is also not favorable for the growth of fungi, which would certainly collect on the wound and reduce the chances of complete recovery. As an additional guard against the formation of fungus, table-salt in quantities mentioned above in treating asphyxia, is good, as also is a solution of carbolic acid, five drops to the gallon of water.
We conclude this description of the various diseases with the homely phrase, "an ounce of prevention is worth a pound of cure," so bearing that in mind, one will see to it that his aquaria and ponds do not suffer from neglect, as that always tells upon the fish.