Health Problems
Not withstanding this, most fish given good husbandry & attention will thrive & be a constant pleasure to those of us, who like to replicate a small piece of nature in our own homes.
The diseases and problems that can afflict fish can be broken down into the following categories:
1)Parasitic
2)Bacteriological
3)Viral
4)Nutritional
5)Toxicological
6)Environmental
7) Other
Although we will not deal with the latter two categories for quite some months from now, in fact these are among the most challenging, & will become the topic eventually of some interesting discussions, but for now we will begin our investigation of diseases, by looking at the first major group, that is the parasitic species, that are endemic to so many of the tropical fish, which for the most part today are bred on farms.
PARASITES OF FISH
Freshwater
In considering these parasites, the Hobbyist should be aware that some parasites essentially need an intermediate host, in order to be able to complete their life cycle. In several cases such an intermediary is a snail, or some form of Invertebrate such as Daphnia, or other similar organisms. In such cases, by eliminating the intermediary we can bring the spread of the infestation to a halt.
In the wild probably a majority of fish are host to one or more parasites, but for reasons addressed in previous articles, they seldom become a major problem or cause of mortality. In fact there is considerable evidence that in some of the more prevalent parasites e.g. White spot ( Ichthyophthirius multifiliis) that exposed fish can develop an immunity against further attack.
Whilst it most cases it is recommendable for the Hobbyist to purchase young specimens, ( as they will live longer, & more easily adapt to the confines of his/her Aquarium), such specimens are also more prone to succumb to attacks by parasites having less size, and body weight to resist the damage that many of the parasites can so easily inflict. For this reason, any purchases, should be carefully inspected, to ensure that there are no "blemishes" of any kind, on the desired specimen, & the buyer should also ensure that no fish are bought from any tank in which any fish are manifesting unfavourable symptoms. Parasites once present in a tank can in so many instances spread rapidly with devastating effects, & a fish that has been exposed & yet appear to be perfect, can break out within a day or so, spreading its parasites to others in your Aquarium.
For those of you that have the possibility , it is advisable to keep all newcomers in a separate quarantine tank, when first purchased. This will give one the chance to ensure that nothing untoward, will be transferred to the principle Aquarium, as it is counterproductive to try treating a fully planted & landscaped Aquarium, when disease breaks out. The period of such quarantine, bearing in mind the life cycles & latent period of so many of the potential problems should be 3 weeks. This is the period used by Government edict in Australia, which is one of the few countries so far, to require all imports of Tropical fish to be so held, in Government approved holding facilities. Such facilities are licensed & examined regularly, all the limited number of approved Importers must keep accurate records, & anyone breaking the rules which are closely & continuously monitored, will have the sanction of repeal of his/her importing license effected without delay.
Therefore if you do take the prudent step to quarantine all new purchases, it is wise to make certain that they are kept for at least two weeks, if not three, before introducing them to their new home. I realize that such goes to a large extent against the "I want it now" , type of society we live in today, but the " I want a cure, that is 100% effective, works in one day or less , & causes no headaches" DOES NOT EXIST, so caution can pay off in spades, as they say.
It is also important to note, that parasitic infestations, often do not kill directly. However because of the damage they cause to the tissues & vital organs of the fish, they frequently cause secondary opportune infections of bacteria & fungi, to invade the fish, bringing about a rapid death of the host, & often spreading the new infection throughout the Aquarium.
In order to avoid the potential spread of any infestation or infection, all nets, or utensils of any kind that may used with your fish, should be kept in a sterilizing solution between uses, & rinsed thoroughly before & after use.