Guppies with some disease, help please

[kimos]

Hi All, thanks for the help in advance.

Tank size: 60L / 15.5G
pH: 7.5
ammonia: 0
nitrite: 0
nitrate: 0
kH: ?
gH: ?
tank temp: 24

Fish Symptoms (include full description including lesion, color, location, fish behavior): Most are lethargic, are not swimming around, they just stay up there, , some with gills red and open, some with skin patches, none are scratching nor seeking oxygen. All of them can stay steady up there, but one of them can't even move forward to catch the food.

Volume and Frequency of water changes: every 2 weeks, 20L / 5G

Chemical Additives or Media in your tank: Started yesterday with Melafix and Pimaxif, also with broad use antibiotic

Tank inhabitants: around 6 guppies, 1 bristlenose, 2 koly loaches

Recent additions to your tank (living or decoration): none

Exposure to chemicals: above medicines

Digital photo (include if possible): video: https/share.icloud.com/photos/0t4Y3GVmAOeHTL8WILzdtfhnA

 

[Colin_T]

Guppies naturally hang around the surface, however yours appear to have flared gills and one has a cream patch on its back. The flared gills can be from poor water quality, gill flukes or low oxygen levels. The cream patch on the back could be a bacterial infection.

The best treatment for guppies is salt.
You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 2 heaped tablespoon per 20 litres of water.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 4 heaped tablespoons per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate will not affect 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.