💧 Why Chlorine & Chloramine Are Harmful to Fish

---

🧪 What They Are

• 🧼 Chlorine (Cl₂ → HOCl/OCl⁻ in water) → Strong oxidizer, kills microbes.
• 🧪 Chloramine (NH₂Cl) → Chlorine + ammonia, more stable, lasts longer in pipes.
• 🚰 Safe for people, deadly for aquariums.

---

⚠️ How They Harm Fish

• 🫁 Gills Burned → Oxidizes delicate tissue → fish gasp at surface.
• 🩸 Blood Damage → Red blood cells destroyed → less oxygen in bloodstream.
• 🧠 Stress & Weak Immunity → Higher risk of disease.
• 🦠 Biofilter Killed → Beneficial bacteria die → ammonia & nitrite spike.
• 🧨 Chloramine Bonus Problem → Breaks into chlorine + toxic ammonia.

---

📊 Sensitivity Levels

• 🚰 Tap water = 1–4 ppm chlorine/chloramine.
• 🐟 Fish stressed at <0.05 ppm.
• 🦐 Shrimp, snails, fry → even more sensitive (zero tolerance).

---

🧪 How to Tell What You Have

• 🔬 Free Chlorine Test → Shows chlorine only.
• 🔬 Total Chlorine Test → Shows chlorine + chloramine.
• ➖ Total − Free = Chloramine present.
• ⚠️ Use salicylate ammonia tests (not Nessler) with conditioners.

---

🧴 How to Remove Them

• 🧴 Water Conditioner → Instantly neutralizes chlorine & binds ammonia from chloramine.
• 🪵 Activated/Catalytic Carbon → Removes chlorine; catalytic carbon removes chloramine (needs good contact time).
• ⚗️ Chemical Reducers (Sodium Thiosulfate, etc.) → Cheap for big systems; needs precision + aeration.
• 🌬️ Aging/Aeration → Works only for chlorine (24–48 hrs). ❌ Not for chloramine.

---

📋 Best Practices for Water Changes

1. 🧾 Know Your Source
   • 📞 Call your local water supplier.
   • 📝 Request a water quality report.
   • ❓ Ask: Do you use chlorine, chloramine, or both?
   • ⚡ Example: Some areas (like yours) use chlorine only, easier to neutralize.
2. 🧪 Test Your Tap → Free & total chlorine before adding to tank.
3. 🧴 Pre-Treat Water → Dose conditioner for the entire bucket/barrel.
4. 💨 Aerate & Mix → Improves oxygen and spreads conditioner.
5. 🧫 Double-Check → Ensure 0 ppm chlorine/chloramine before adding.

---

🚩 Warning Signs of Trouble

• 😮 Gasping at surface after water change.
• 🔴 Red or inflamed gills.
• 🌀 Erratic swimming or darting.
• 📉 Biofilter crash (ammonia/nitrite spike).
• ⚰️ Sudden unexplained deaths.

---

🌟 Pro Tips

• 🧴 Always treat all new water (not just what’s in the tank).
• 🧪 Test often — some utilities switch seasonally between chlorine & chloramine.
• 🪴 Plants, shrimp, fry → extra sensitive.
• 🛠️ Fish rooms: Use inline catalytic carbon + storage barrels.
• 📅 Keep a logbook → track test results & supplier updates.

---

✅ Bottom line: Chlorine & chloramine protect people, but they’re lethal to aquariums. Always know your water source, treat correctly, and test before water touches your fish.