The fish has excess mucous over its body. This is caused by something in the water irritating the fish. It can be ammonia, nitrite, nitrate, or some other chemical that has entered the water. A big water change and gravel clean is the recommended treatment.
The fish also appears to have red in the mouth and white around it. Again the white is excess mucous. The red could be an infection. A big water change and gravel clean might help. I would then see how the fish looks over the next 24 hours.
If you need medications, salt and clean water can help with most things. See below for salt instructions.
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FIRST AID FOR FISH
Test the water for ammonia, nitrite, nitrate and pH.
Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.
Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.
Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.
Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.
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SALT
Using Salt to Treat Fish Health Issues.
For some fish diseases you can use salt (sodium chloride) to treat the ailment rather than using a chemical based medication. Salt is relatively safe and is regularly used in the aquaculture industry to treat food fish for diseases. Salt has been successfully used to treat minor fungal and bacterial infections, as well as a number of external protozoan infections. Salt alone will not treat whitespot (Ichthyophthirius) or Velvet (Oodinium) but will treat most other types of external protozoan infections in freshwater fishes. Salt can treat early stages of hole in the head disease caused by Hexamita but it needs to be done in conjunction with cleaning up the tank. Salt can also be used to treat anchor worm (Lernaea), fish lice (Argulus), gill flukes (Dactylogyrus), skin flukes (Gyrodactylus), Epistylis, Microsporidian and Spironucleus infections.
You can add rock salt (often sold as aquarium salt), swimming pool salt, or any non iodised salt (sodium chloride) to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres (5 gallons) of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.
Keep the salt level like this for 1 to 2 weeks.
The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.
After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.
If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.
When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.
I already told you the measurements of the tank (30cm d x 45cm h 30cm l) in the dwarf gourami thread. And the tank was cycled for a week and a bit before adding the fish almost a year ago and continues to cycle, with partial water changes every few weeks.
