Ich (White Spot Disease) in Fish: Signs and Treatment

Ich, also called white spot disease, is one of the most common fish diseases. It is caused by a parasite and spreads fast, but it can be treated if you catch it early. Here is how to spot it, treat it, and keep it from coming back.

What Is Ich?

Ich is caused by a parasite called Ichthyophthirius multifiliis. It attaches to the fish, makes small white dots, and then drops off to multiply in the tank. Only the free-swimming stage can be killed by treatment, so you need to treat the whole tank for the full time.

Signs of Ich

• Small white spots like grains of salt on the body, fins, or gills
• Fish rubbing against decor or the substrate
• Clamped fins
• Fast breathing
• Less appetite or hiding

What Causes Ich?

• New fish that carry the parasite
• Stress from temperature swings
• Poor water quality
• Overcrowding

Quarantine is the best prevention. See how to set up a quarantine tank.

Keep Ich Medicine on Hand

We recommend keeping an ich medication in your fish room at all times. Ich spreads quickly, and having treatment ready can save your fish. It is better to have it and not need it than to wait for a delivery while your fish get worse.

Two products we recommend are:

• Ich-X
• Nox-Ich

Always follow the directions on the bottle for dose and treatment time.

How to Treat Ich

1. Confirm the spots. Small white dots all over the body are the classic sign.
2. Test your water and fix any problems. Do a water change.
3. Start your ich medication. Use Ich-X or Nox-Ich and follow the bottle directions exactly.
4. Raise the temperature slowly. Warmer water speeds up the parasite's life cycle, so the medication can reach it sooner. Do not raise it faster than your fish can handle. Many tropical fish can go to the low-to-mid 80s°F. Goldfish should only be warmed slightly, to about 78 to 80°F.
5. Add lots of air stones. Warm water and medication hold less oxygen, so extra aeration is important. Add more air stones than you think you need.
6. Treat for the full time. Keep treating for as long as the bottle says, even after the spots disappear.
7. Vacuum the substrate daily. This removes parasites that fall off.

Remove carbon from your filter during treatment because it can absorb the medication.

Be Careful With Scaleless Fish

Scaleless fish, such as loaches and some catfish, are much more sensitive to ich medication. Read the label for your product, and use a lower dose or a different treatment if the label says so. Shrimp, snails, and other invertebrates can also be harmed, so move them to a separate tank before treating.

Treating Ich in Goldfish

Fancy goldfish are sensitive, so keep the water very clean, warm it slightly, and keep aeration high. Follow the bottle directions for your medication.

Treating Ich in Bettas

Bettas do well with warm, stable water around 80 to 82°F, clean water, and good aeration while treating. See our betta fish care guide.

How to Prevent Ich

• Quarantine all new fish for 2 to 4 weeks.
• Keep temperature steady.
• Do weekly water changes. See our water change guide.
• Do not overcrowd your tank.
• Feed a good diet.
• Keep ich medicine on hand.

Frequently Asked Questions

How long does ich take to treat?

Usually 1 to 2 weeks, depending on temperature and the medication directions.

Can ich go away on its own?

Rarely. It usually gets worse, so treat it quickly.

Can I treat just the sick fish?

No. The parasite is in the whole tank, so treat the whole tank.

Is ich dangerous to people?

No, it only affects fish.

Do I need to keep treating after the spots are gone?

Yes. Finish the full treatment time on the bottle, because parasites may still be in the water.

What medicine do you recommend for ich?

We recommend Ich-X or Nox-Ich. Follow the bottle directions, and keep a bottle on hand.

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