The Invisible Assassin: Why Tap Water Kills Bettas (And How to Fix It)

You drink tap water. It’s safe for you.

So why does it kill your fish?

Because you have lungs. Your Betta has gills.

To a fish, tap water is not water—it is Bleach.

1. What is Chlorine?

Chlorine is a chemical added by the water company (Indah Water / PBA / Syabas) to kill bacteria in the pipes so you don’t get diarrhea.

• For Humans: It is safe in small amounts.
• For Fish: It is a deadly poison.

2. Why Does It Kill? (The Chemical Burn)

When a Betta swims in untreated tap water, the Chlorine attacks two things:

1. The Gills: It physically burns the delicate gill tissue. Imagine breathing in a room full of smoke and bleach fumes. Your fish gasps at the surface because his gills are burned and can’t absorb oxygen.
2. The Slime Coat: Fish have a slimy layer on their skin that protects them from disease. Chlorine strips this off, leaving them raw and open to bacteria.

How fast does it kill?

• High Concentration: The fish can die in 30 minutes to a few hours.
• Low Concentration: He might survive a few days, but his gills are permanently damaged, and he will die of stress or infection later.

3. The Big Question: Before or After?

Question: “Can I add the fish first, then pour the Anti-Chlorine in?”

Answer: NO.

Think of it like a gas chamber.

Would you put on a gas mask before you walk in, or walk in, take a few deep breaths of poison, and then put the mask on?

The “Premix” Rule:

1. Fill your bucket with tap water.
2. Add the Anti-Chlorine drops.
3. Swirl it around for 1 minute.
4. NOW pour it into the tank with the fish.

“Oops, I already added the fish!”

If you made a mistake, add the Anti-Chlorine immediately. Pour it near the filter flow so it mixes fast. Your fish might suffer some burn, but it is better than doing nothing.

4. The “24-Hour” Myth (Why Aging Water Fails)

Your grandfather probably told you: “Just leave the water in a bucket for 24 hours, the Chlorine will evaporate.”

This is outdated advice.

Modern water companies (especially in Malaysia) now use Chloramine.

• Chlorine: Evaporates in 24 hours.
• Chloramine: Is Chlorine bonded with Ammonia. It does NOT evaporate. You can leave that bucket for a month, and it will still be toxic.

Verdict: You cannot cheat. You MUST use a chemical Water Conditioner.

5. What Should You Buy?

• The Gold Standard: Seachem Prime.
  • Why: It removes Chlorine, Chloramine, and detoxifies Ammonia for 24 hours. It is concentrated (1 drop treats 1 gallon). Expensive bottle, but cheapest per use.
• The Budget Choice: Generic “Anti-Chlorine” (The RM 5 Bottle).
  • Why: It works for Chlorine, but sometimes fails on Chloramine. It does nothing for Ammonia. Better than nothing, but not the best.

Summary: The Safe Water Protocol

The Shop Guy’s Verdict

A bottle of Anti-Chlorine costs RM 5 to RM 30.

A dead Betta costs you sadness.

Don’t be cheap. Treat every drop of water that goes into your tank. Even if you are just “topping up” a little bit.