Betta fish typically exhibit the following distinct signs when approaching death. By considering their living environment and potential diseases, you can intervene in a timely manner:
Abnormal Behaviors
Sudden loss of activity: They may stop swimming abruptly, stay at the bottom of the tank for long periods, or lie on their sides, showing slow responses to stimuli.
Rapid breathing: The gills open and close at a noticeably faster rate, and the gill color may darken or turn a deep red.
Refusal to eat: They show no interest in food, even live bait like bloodworms, often accompanied by weight loss.
Physical Changes
Discoloration or lesions: Their body color becomes dull; white spots (a sign of water mold) or black spots (indicating tuberculosis) may appear, and fins and tails may shrink or ulcerate.
Swelling or raised scales: The abdomen may swell abnormally (a symptom of dropsy), scales may stand upright (scale protrusion disease), and there may be an increase in mucus on the body surface.
Parasite-related symptoms: They may rub against the tank frequently, swim erratically (due to itchiness from pepper disease), or have flocculent substances attached to their bodies.
Environment-Related Signs
Reactions to poor water quality: When ammonia levels are too high, symptoms like fin rot and lethargy may occur, with no improvement even after water changes.
Temperature stress: Sudden changes in water temperature can cause them to flip over or twitch, especially when water is changed or the heater malfunctions.
Timelines to Death for Different Causes
Acute illnesses (e.g., bacterial infections): Death can occur quickly within 3-7 days, accompanied by symptoms of organ failure.
Chronic illnesses (e.g., parasites): They may gradually lose weight over 1-2 months, eventually succumbing to organ failure.
Oxygen deprivation or poisoning: Mass deaths can happen within hours, commonly in overcrowded tanks or water bodies with eutrophication.
Key Handling Suggestions
If you notice the above signs, take immediate action:
Isolate the sick fish to prevent spreading to others.
Test water quality (ammonia, nitrite, pH levels), perform an emergency water change of 1/3, and raise the temperature to 28°C.
Use targeted medications: For example, methylene blue for water mold, and metronidazole for dropsy.
If the fish is already in an advanced stage, such as lying on its side with weak breathing, the success rate of treatment is very low.