Why Is My Guppy Dying? The “Emergency Room” Guide (Worms, Ich, and Stress)

It is the worst feeling in the hobby.
You bought a pair of beautiful Guppies on Saturday. By Tuesday, one is floating at the top. The other one is sitting at the bottom, fins clamped tight, looking miserable.

You ask: “What did I do wrong? I fed them, I have a filter, the water is clear.”

Often, it isn’t your fault. Guppies are mass-produced in huge farms. They are stressed during shipping. By the time they reach your tank, their immune system is weak, and parasites take over.

Here are the Big 3 Killers of Guppies in Malaysia, and how to save them before it’s too late.

1. The “Red Thread” (Camallanus Worms)

This is the #1 silent killer in local farm-bred Guppies.

• The Symptom: Your Guppy looks skinny (wasting away) even though it is eating. If you look closely at its anus (vent), you see tiny red threads sticking out.
• What it is: A nasty internal parasite called Camallanus. It sucks the blood and nutrients from your fish.
• The Cure: Normal “Blue Water” (Anti-Ich) will NOT work. You need a specific de-wormer.
  • Look for medication containing Levamisole.
  • In Malaysia, a popular choice is “Manaus-Aquarium Levamicil” or generic deworming flakes.
  • Warning: Treat the whole tank. If one fish has it, they all have it.

2. The “Sugar Coating” (Ich / White Spot)

This usually happens during the rainy season or if you keep your tank in an air-conditioned room without a heater.

• The Symptom: The fish looks like it has been sprinkled with salt or sugar grains. It might rub its body against rocks (“flashing”).
• What it is: A microscopic parasite that burrows into the skin. It loves cold water.
• The Cure: You don’t always need harsh chemicals.
  1. Raise the Heat: Ich dies at 30°C. Since our weather is already hot, just turn off your fan or add a small heater to bump it to 30°C for 3 days.
  2. Aquarium Salt: Add 1 tablespoon of Aquarium Salt per 5 gallons. It kills the parasite in the water stage.

3. The “Clamped” Fin (Stress/Bacteria)

This is a sign that the fish is on death’s door.

• The Symptom: The tail fan is folded shut (clamped). The fish wobbles in place. It breathes fast.
• What it is: This is not a specific disease; it is a symptom of Stress. It could be bad water quality (Ammonia), wrong pH (too soft), or a bacterial infection eating their slime coat.
• The Cure:
  1. Check Water: Test for Ammonia. If high, do a 50% water change immediately.
  2. The “Salt Bath”: If the water is fine, the fish might have a bacterial issue. Prepare a separate container with tank water and a higher dose of salt. Let the fish swim in it for 15 minutes, then put it back. This strips bacteria off the skin.

4. The “Rotting” Tail (Fin Rot)

Common in Guppies with huge tails (like Delta tails).

• The Symptom: The edges of the beautiful tail look ragged, white, or black. It looks like it is dissolving.
• The Cure: Clean Water. Fin Rot is almost always caused by dirty water. Do daily 20% water changes for a week. Adding Indian Almond Leaves (Ketapang) also helps because the tannins act as a natural antiseptic.

5. The Golden Rule: Quarantine

How do you stop these diseases? Don’t let them in.

When you buy new Guppies from the shop, do not put them in your main tank immediately.
Keep them in a separate small container or “Quarantine Tank” for 1 week. Observe them. If you see the “Red Threads” or “White Spots,” treat them there. Do not infect your whole colony.

Guppies are small, but they are fighters. If you catch these signs early—especially the worms—you can save them. Keep a packet of Aquarium Salt and some Dewormer in your drawer. It’s better to have it and not need it, than to need it at 10 PM on a Sunday.