Spotting a health problem early and treating it correctly can be the difference between a quick recovery and a fish that never bounces back. This guide walks through six of the most common betta ailments — fin rot, ich, velvet, dropsy, swim bladder disorder, and popeye — with the symptoms to watch for and the specific steps to treat each one. If you'd rather start with a broader picture of disease categories first, check out our outline of betta fish diseases.

Before treating anything, always move your betta to a separate hospital tank if possible. This isolates medication to the sick fish, protects tankmates, and lets you monitor recovery without disturbing your main setup. A bare 2-3 gallon container with a heater and sponge filter works well for short-term treatment.

Fin Rot

Symptoms: Ragged, frayed, or blackened fin edges that appear to be dissolving. In advanced cases the rot creeps toward the body and fins may develop a white or red rim.

  1. Test your water immediately — ammonia and nitrite should read 0 ppm, and nitrate should stay under 20 ppm.
  2. Perform a 25-50% water change and increase water change frequency to twice weekly during treatment.
  3. Add an aquarium salt treatment (1-2 tablespoons per gallon) or a broad-spectrum antibacterial medication such as one containing kanamycin or erythromycin, following label dosing.
  4. Maintain water temperature at 78-82°F to support immune function without stressing the fish.
  5. Continue treatment for 7-10 days, watching for fin regrowth as a sign of recovery.

Ich (White Spot Disease)

Symptoms: Tiny white grains resembling salt scattered across the body and fins, often paired with scratching against decor and clamped fins.

  1. Raise the tank temperature gradually to 82-86°F, which speeds up the parasite's life cycle and makes it vulnerable to treatment.
  2. Treat with an ich-specific medication containing malachite green or formalin, dosed exactly per label instructions.
  3. Add aquarium salt at 1 tablespoon per gallon to help the parasite detach.
  4. Continue treatment for a full 10-14 days even after visible spots disappear, since the parasite has a multi-stage life cycle and can return if treatment stops early.
  5. Vacuum the substrate daily to remove free-swimming parasites before they can reinfect your betta.

Velvet

Symptoms: A fine gold or rust-colored dusting on the skin, best seen by shining a flashlight across the fish in a darkened room. Bettas with velvet often clamp their fins, rub against objects, and lose appetite.

  1. Dim or cover the tank — the parasite responsible for velvet relies partly on light for part of its life cycle.
  2. Raise temperature slightly to around 82°F and add aquarium salt.
  3. Treat with a copper-based medication formulated for velvet, carefully following dosage since copper can be toxic to invertebrates and sensitive fish.
  4. Treat for at least 10 days to break the parasite's reproductive cycle.
  5. Improve water quality with more frequent water changes, since velvet often takes hold when a betta is already stressed.

Dropsy

Symptoms: A swollen belly with scales protruding outward in a pinecone pattern, lethargy, and loss of appetite. Dropsy is a symptom of severe internal bacterial infection and organ failure, not a disease itself, and is often difficult to reverse.

  1. Isolate the betta immediately in a hospital tank with pristine, 0 ppm ammonia water.
  2. Add Epsom salt (not aquarium salt) at 1-3 teaspoons per gallon to help draw excess fluid out of the body.
  3. Treat with a broad-spectrum antibiotic formulated for internal bacterial infections.
  4. Keep water extremely clean with daily partial water changes to reduce additional bacterial load.
  5. Be realistic about prognosis — dropsy is frequently caught in late stages and survival rates are low, though early intervention gives the best chance.

Swim Bladder Disorder

Symptoms: Difficulty swimming upright, floating sideways, sinking to the bottom, or struggling to reach the surface. This is usually caused by overfeeding or constipation rather than infection.

  1. Skip feeding for 24-48 hours to let the digestive system reset.
  2. Offer a small piece of skinned, cooked pea after the fast to help relieve constipation.
  3. Review your feeding routine — overfeeding and swallowed air from surface feeding are the leading causes, so switch to sinking pellets if needed.
  4. If symptoms persist beyond a week or worsen, consider a bacterial cause and treat with an antibacterial medication.

Popeye

Symptoms: One or both eyes bulge outward abnormally, sometimes with cloudiness. It can result from bacterial infection, injury, or poor water quality.

  1. Test and correct water parameters immediately — popeye is frequently linked to ammonia or nitrite exposure.
  2. Perform a 25-50% water change and increase filtration if needed.
  3. Treat with a broad-spectrum antibacterial medication if no improvement follows the water change.
  4. Avoid Epsom salt unless swelling is severe, and monitor closely since popeye affecting only one eye often has a better prognosis than bilateral cases.

Frequently Asked Questions

Can I treat multiple diseases at once?

It's best to identify the primary issue and treat it specifically rather than combining medications, since mixing treatments can stress your betta further or cause harmful chemical interactions.

How long should I keep a betta in a hospital tank?

Continue treatment for the full recommended course, typically 7-14 days depending on the illness, even if symptoms appear to resolve early.

Should I medicate the main tank instead of using a hospital tank?

Whenever possible, treat in a separate hospital tank. Medicating a full display tank can harm beneficial bacteria, live plants, and any tankmates.

For the underlying husbandry that prevents most of these problems from developing in the first place, see our guide to preventing betta fish disease and our full betta fish care guide.