Common Diseases of Guppies
Maintaining good water quality is the key to a healthy guppy tank. The main cause of poor water quality is overfeeding, which leads to pollution and the accumulation of harmful substances from dirty filters. By feeding in moderation and regularly cleaning the filters, you can prevent water quality issues. Regular water changes are also necessary, but avoid large, sudden changes, as this can harm guppies.
Water temperature fluctuations are a major concern for guppies, as they are cold-blooded animals. Regardless of whether the water is hot or cold, it can negatively affect the fish's normal functions, especially significant temperature changes.
Avoid rough handling of the fish's body, as guppies have delicate skin. When using a net to catch them, be extra careful to avoid injury, as even minor damage can lead to bacterial infections. If using your hands, avoid using your nails.
Introducing sick fish is a common cause of illness in guppies. When purchasing new guppies, always check for signs of illness or observe them in a quarantine tank for three to five days before introducing them to your main tank.
1. White Spot Disease: White spots (approximately 1mm in diameter) appear across the body and will spread throughout the fish if left untreated, leading to weakness and eventual death. It’s a typical disease for freshwater fish. Although guppies don’t usually get it, it’s important to be vigilant. Cause: Triggered by trematodes (flukes) causing this disease, with the white spots being the parasites themselves.
2. Fin Rot: Yellow-white mucus attaches to the fin, gradually spreading to other fins and eventually rotting. It is characterized by decaying fins, and in severe cases, fins may break off. The fish loses appetite and becomes weak, eventually dying. Cause: Caused by infection from Keratitis (Carlsberg bacteria), often due to fish fighting and rough handling.
3. Cotton Wool Disease (Water Mold): This disease appears in cooler seasons (spring, autumn, winter). Water mold (formerly known as cotton wool disease) colonizes the skin, initially appearing on the edges of the fins and gradually spreading throughout the body, leading to skin rot. The disease causes loss of appetite, reduced activity, and eventual death. Cause: Besides low water temperature, wounds or infestations by anchor worms, fish lice, etc., create entry points for molds from the Fusarium fungus.
4. Scale Rot: Also known as ‘Standing Scale Disease’, the scales on the body stand erect, and the body swells. The disease is named because the scales appear to be standing on end. If the disease progresses, the scales will fall off, preventing the fish from swimming properly and eventually leading to death. Cause: Caused by infection from Keratitis (Carlsberg bacteria).
5. Mouth Rot: White cotton-like patches appear around the mouth and gills, preventing the fish from feeding. Eventually, it spreads to the gill slits, leading to suffocation and death. Cause: Similar to Fin Rot, it’s caused by Keratitis (Carlsberg bacteria) infection.
