Disclosure: HabitatCraft is a participant in the Amazon Services LLC Associates Program. As an Amazon Associate we earn from qualifying purchases at no extra cost to you.
Ich (white spot disease) is one of the most common diseases in freshwater aquariums and one of the most treatable when caught early. It’s caused by a parasitic protozoan and is highly contagious to other fish in the same tank. The good news: if you act quickly, ich is curable in most cases without lasting harm to your betta.
What Is Ich?
Ich is caused by Ichthyophthirius multifiliis, a parasitic protozoan that completes part of its life cycle on the fish’s body. The visible white spots are cysts containing the parasite in its feeding stage. The parasite is only vulnerable to treatment during its free-swimming stage — not while it’s attached to the fish — which is why treatment must be maintained for a full cycle.
What Ich Looks Like
- Small white spots on the body, fins, and gills — resembling grains of salt or sugar
- Flashing (rubbing against decor, substrate, or glass)
- Clamped fins
- Rapid gill movement or labored breathing (especially if gills are affected)
- Loss of appetite and lethargy in moderate to severe cases
Early ich may appear as just one or two spots. By the time spots are numerous, the infection is already well established. Check your betta regularly under good lighting.
Ich vs. Other White Spot Conditions
| Ich | Uniform white spots, grain-of-salt size, spread across body and fins |
| Velvet | Gold or rust-colored dust, visible under a flashlight held at an angle |
| Columnaris | White or grey patches, often irregular, may look cottony |
| Lymphocystis | Cauliflower-like growths, usually on fins, not uniform spots |
What Causes Ich
Ich is introduced to a tank through new fish, plants, or equipment that have been in contact with infected water. It can also be present in a tank at low levels and become active when a fish’s immune system is suppressed by:
- Sudden temperature drops
- Poor water quality (elevated ammonia or nitrite)
- Stress from transport, a new tank, or aggressive tankmates
- Overcrowding
How to Treat Ich
Step 1: Raise the Temperature
Raise the tank temperature gradually to 86°F (30°C) over 24–48 hours — no more than 2°F per hour. Higher temperatures accelerate the ich life cycle, causing the parasite to reach its vulnerable free-swimming stage faster. At 86°F, the ich life cycle completes in approximately 3–4 days instead of 7–10 days at normal temperatures. Most bettas tolerate 86°F (30°C) for the duration of ich treatment when well oxygenated.
Step 2: Increase Aeration
Warmer water holds less dissolved oxygen. Add an air stone or increase surface agitation during treatment to ensure adequate oxygenation.
Step 3: Treat With Medication
Use an ich-specific medication. Effective options include:
- Ich-X (Hikari) — widely recommended, safe for bettas and most scaleless fish, contains malachite green and formalin
- Super Ich Cure (API) — effective broad-spectrum ich treatment
- Kordon Rid-Ich Plus — another reliable malachite green/formalin option
Remove activated carbon from the filter before treating — it will absorb the medication. Follow dosing instructions and treat for the full recommended duration, even if spots disappear early. Spots disappearing from the fish means the parasite has dropped off to reproduce — treatment must continue through the free-swimming stage to break the cycle.
Step 4: Maintain Treatment for the Full Cycle
Continue treatment for at least 7 days at elevated temperature, or follow the medication’s recommended duration. Perform small water changes (10–15%) every other day to remove free-swimming parasites from the water column, and re-dose medication after each water change.
Step 5: Return to Normal Temperature
Once treatment is complete and no spots have been visible for at least 3–4 days, gradually lower the temperature back to 78–80°F over 24–48 hours.
How to Prevent Ich
- Quarantine new fish: Keep new fish in a separate tank for 2–4 weeks before introducing them to an established tank
- Quarantine new plants and equipment: Rinse and dry, or quarantine, anything that has been in contact with another tank
- Maintain stable temperature: Sudden drops trigger outbreaks — use a reliable heater and thermometer
- Maintain water quality: Healthy fish with strong immune systems resist ich more effectively
See our Best Aquarium Heaters, Best Aquarium Thermometers, and Best Water Test Kits guides.