1) Small, white spots on the head, body and fins. Whitespot (Ichthyophthirius) A very common disease (especially in a new aquarium). There are several formulas around, dose the fish quickly before the parasite spreads. Salt could be used (1 teaspoon per galloon).
2) Fraying of the soft tissue (fin membrane) Fin Rot, the disintegration of the fins Use medication before a secondary infection occurs, it will take several days before there is serious fin damage. Could use salt bath (1 teaspoon per gallon)
Appearance of a whitish film over the eye of the fish Poor water quality, poisoning (Chlorine) or Eye Fluke Poor water: Water changes are required. Poisoning: Make sure to condition tap water. Eye Fluke: Use medication
3) Fish are gasping, on the bottom of the aquarium, red streaks around gills Most probably oxygen starvation, or a Gill disease You have too many fish, an air punp may help. Gill diseases are quite rare, you could actually see the gills rot away: use medication.
Scales seem to be raised, fish are bloated. Dropsy (Ascites) Dropsy is more of a sympton than an actually disease yet, and is quite common. Most associated with a bacterial infection (cause could be wide - poor water conditions are often the culprit. Meds can be used, but dont always work.
Small, worm like parasites attached to fish, fish scraping against rocks. Anchor worm (lernea) There are many Crustacean Parasites around, and can be exported into your water. Meds are available.
6) Dull colour (mucus), detached skin, fraying of the fin. Mucus Hyperproduction. This called by caused by Slime disease (parasite, meds available), poor water conditioners (high Nitrogenous wastes), fFukes, stress.
A word of warning with using medication: Obviously people want to save their fish, so they go and buy a product, and sometimes these can be quite effective. But a word of warning - some meds can be very detrimental in the long term. Treatments whitch use Malachite Green and Methylene Blue can be useful treatments for parasites and Fungus, unfortunately they can destroy our beneficial bacteria, and then you can get a Ammoni/Nitrite peak for some time. Also some meds demand it that they remove Carbon/Zeolite for the duration of the treatment - this can effectively start up a mini-cycle as the Carbon/Zeolite have lost their bacteria.
Salt bath: So a salt bath is a good way of treating the fish without damaging the bacteria we need. It is a good antiseptic and fungicide. If you are using high doses, its best to try to gradually raise the concentration, so the fish don't become stressed. Sometimes it can be effective to use a short salt bath, with higher salt concentration (such as fungal infection - 10G/Litre for 30 min).
2007-06-08 10:44:07 補充:
Your fish will not die if you give suitable medication esp. salt bath to it.
參考: Book