Thought id post this as there seems to be a few questions about fish this week or so.

Disease and Causes Symptoms Reason for Infection Action Treatment
Ulcers
Caused by Pseudomonas and Aeromonas bacteria
Pinky-white open wounds, often with a white edge and sometimes secondarily infected by fungi and other bacteria. Very poor water quality or an excessively high pH level. Minor scratches can become infected if conditions are poor. Also commonly affects newly imported Koi and goldfish. Test the water for signs of ammonia and nitrite. Conduct a large water change to reduce pollution levels. Fish lose salts quickly through open wounds, so add aquarium salt at a dose of 1-3g/litre. Use an anti-ulcer treatment. If treatment fails, a vet can prescribe stronger antibiotics.

Cloudy eye
Caused by poor water quality, poor diet, eye flukes, corneal damage, bacterial infection.
Entire surface or lens of eye takes on a cloudy, opaque appearance. There may be a build-up of mucus on the outer surface. Most commonly caused by poor water conditions. A lack of vitamins in the diet may also cause clouding. On rare occasions digenetic flukes, such as Diplostomum, can cause problems. Improve water conditions. Use a good quality food containing added vitamins. Improving water conditions usually cures cloudy eyes. Eye flukes are uncommon and can be difficult to accurately diagnose and treat.

Dropsy
Usually caused by bacterial infection. Viral infection, nutritional, metabolic and osmoregulatory problems can also be responsible.
Swelling of the body cavity due to a build-up of fluid. Scales become raised giving a pinecone-like appearance. One or both of the eyes may be protruded. Usually triggered by poor water quality, especially the presence of ammonia and nitrite. Often confined to individual fish. Test water and improve water conditions immediately. Aquarium salt at a dose of 1- 3g/litre can help to prevent salt loss. Can be difficult to treat. A broad spectrum anti- bacteria treatment is the best option in most cases.

White spot
Caused by Ichthyophthirius multifiliis parasite
Small white spots, about the size of a salt grain, on the skin, fins and gills. Stress related. Usually a consequence of poor or incorrect water conditions, fluctuating temperature and general poor husbandry. Sensitive species may develop white spot as a result of being introduced to a new aquarium. Ensure the water is free of pollution and isolate cause of stress. Treat promptly with an anti-parasite medication. It may be necessary to raise the water temperature to improve the effectiveness of the treatment. Wounds left by parasites may become secondarily infected.

Bacterial infection
Caused by Aeromonas and Pseudomonas bacteria
Reddening of the skin or fins; ragged fins with signs of infection, open sores. Common on many newly imported fishes. Often accompanied by other diseases, including fungi. Poor water conditions, especially the presence of ammonia and nitrite. Wounds resulting from poor handling, transport or fighting may become secondarily infected by these bacteria if conditions are poor. Improve water conditions, and treat promptly. Use a proprietary treatment as soon as possible. Aquarium salt at a dose of 1- 3g/litre can help prevent salt loss. Severe infections may require prescription medications from a vet.

Fungus
Caused by Saprolegnia and Achlya
Fluffy growths affecting wounds on the skin and fins of freshwater fishes. Usually a secondary infection that invades wounds left by ulcers and parasites, including whitespot. Rarely a problem in tanks with good water quality. Improve water conditions and treat promptly. Standard anti- fungal medications, such as methylene blue, are usually very effective, but may affect filtration and water quality. When the disease occurs on open wounds, aquarium salt at a dose of 1-3g/litre can help reduce salt loss. Cotton-wool disease (Flexibacter) looks similar but is caused by bacteria and may require a different treatment.

Finrot
Caused by Aeromonas, Pseudomonas or Flexibacter bacteria
Frayed fins, often with a pale pinky-white edge and some blood in the fin tissue. The bacteria are present on most fish. Stress from poor water conditions usually triggers an infection. Nipped fins may become secondarily infected if water is polluted. Some wounds may also be attacked by fungus. Improve water conditions. Isolate nippy fishes. Treat promptly with a finrot or anti-bacteria treatment to prevent the further spread of the disease. Consider adding salt (1-3g/litre) to reduce the loss of salt by the fish. Ensure that water stays free of pollution during treatment.

Swimbladder disorder
Caused by bacterial infection, incorrect diet, trapped gas, physical deformities.
Fish have difficulty swimming to the surface, or to the lower levels of the tank. Commonly affects egg-shaped fancy goldfish. Sometimes caused by poor water quality. Genetic problems in selectively-bred goldfish. Improve water conditions. Feed less dried foods, or pre-soak pellets and flakes so they don't swell the gut. Feed Daphnia, which acts as a laxative. Change diet and improve water conditions. Treat with a specialist anti-bacteria treatment. Fancy goldfish suffering from physical deformities will not recover.

Lymphocystis
Caused by an iridovirus
The virus causes crusty grey-white lumps to develop on the skin and fins. These may affect freshwater or marine fishes, and sometimes take on the colour of the underlying skin. These lumps are clusters of enlarged cells. The disease is viral, but may be triggered by stress, poor handling or poor water. Some fish may carry the virus without showing symptoms. The disease rarely kills, although lesions may become secondarily infected. Ideally, infected fish should be isolated. There is no known treatment. Some vets recommend the surgical removal of the lesions.

hope that helps

Usually a consequence of poor or incorrect water conditions, fluctuating temperature and general poor husbandry.

New tank, it's got a filter and air pump. All water treated with an appropriate de-contaminator and I also pre-seeded with a bacteria start treatment. Ran the tank for 5 days before introducing fish. We've got some auto-balance stuff and stress treatments, will try them.

New tank, it's got a filter and air pump. All water treated with an appropriate de-contaminator and I also pre-seeded with a bacteria start treatment. Ran the tank for 5 days before introducing fish. We've got some auto-balance stuff and stress treatments, will try them.

im asuming you got under gravel filter the others are a waist of time on there own because when you clean the filters out your actualy cleaning out all the good stuff as well.Least your going the right way about things a lot of ppl buy fish and dont prepare there tanks first or do so the same day.

Just my opinion but...I think that external filters are just as good than UGF's, if you clean out the media in tank water, then you don't kill the beneficial bacteria that live in them.

beneficial bacteria live idealy in the gravel so if ppl clean there tanks correctly it stays there were as if your using the external the beneficial bacteria is fillted out of the water its also then destroyed when the filter is cleaned or replaced.Theres a lot of cheap external filters that just are a waist of time as they need cleaning too often you may have a good unit but still say all the good stuff is being pulled away from the water .But if it works good for you then who am i to argue.lol Hey how the heck did this start pmsl

We have an in-tank filter. Not under gravel. But it's only a tiny little tank.

We have an in-tank filter. Not under gravel. But it's only a tiny little tank.

i would change it to a under gravle u can buy a over sized fillter and cut it down to fit you will find them much better.

Arn't UGF hard to clean out though? Just a point.

Arn't UGF hard to clean out though? Just a point.

yes it is a big job when it dos come to doing them but a small tank with a good pump ect can be left for months you just filter out 1/4 of the water and top back up
bigger the tank the better 6months easly possible in bigger tanks i set a 1ft tank up for a friend with ugf thats lasted 3 months water is just starting to show a bit clowdy thats with cold water fish .

Are you talking about cleaning the UGF every few months, or doing water changes every few months?

Are you talking about cleaning the UGF every few months, or doing water changes every few months?
You can buy a suction filter to remove deposits from gravle
no just changing part water when needed UGF dosnt realy need touching until it really needs it.

I would really change the water by a regime, it isnt just the cloudyness of water that matters. Depending on the size/type of fish you own water changes should be done atleast once every 2 weeks I would suggest.

This would help with alot of fish health problems

we never ever stripped down our UGF, just gave it a good weekly clean with a gravel cleaner syphon to remove the detritus.
another point worth mentioning: the FIRST thing you should do if you have sick or dying fish is TEST THE WATER, for pH, ammonia and Nitrite. Many health problems are caused by poor water quality and of course, treatments should never be added to the water until both ammonia and Nitrite are Nill
I no langer have an aquarium, but do have a 5000 gallon Koi pond. Get the water quality wrong in there and you are talking some seriously expensive dead fish

When it comes to changing the water in your aquarium, the best advice is to not change it all at once. I'm not saying that you shouldn't change it at all, but do it gradually. 1/3 or 1/4 of its volume
changing it all every few weeks is just asking for problems unless of cousre you have no ugf ect.

It is generally considered good practice to change your water every week, this removes harmful chemicals like ammonia, nitrate and nitrite, to name a few.

For reading:
http://www.cichlid-forum.com/articles/water_changes.php

http://www.practicalfishkeeping.co.uk/pfk/pages/show_article.php?article_id=65

Both are from highly reputable sources, as they state in them, the frequency and amount of water changes varies for the number/type/size of the fish and aquarium, but as a general rule, do a water change once a week, this is increased for delicate (discus) or messy fish.

But I agree, you shoudnt change all your water during a water change.

Well it also depends on the filter also.

The point of the filter is to remove those harmful chemicals from the water isn't it? It filters out the fish poo and stuff, and gives a place for a lot of bacteria to breed. The bacteria change the ammonia into nitrate which is less harmful, which is then changed into nitrite by a 2nd bacteria and then plants absorb the nitrite and turn into food that the fish eat.

Perhaps an undergravel filter means that you vastly increase the number of Ammonia -> Nitrate bacteria?

The filters only provide surface area for ammonia to be broken down to nitrite, then in turn to nitrate (less harmful to fish, but still toxic). Plants do consume nitrate, however I personally wouldn't rely on plants alone, a good water shedule will make sure that the water is good quality for your fish to thrive.