Learning Community > Aquarium Setup > 6. Heater

Heaters For Your Aquarium

“More Than Just a Warm Touch”

Ah, Singapore—the land of kopi, hawker food… and relentless heat. 🌡️
With average outdoor temps reaching 35°C, you’d think aquarium heaters are the last thing we’d ever need, right?

Well—yes and no. Let’s break it down.

Do You Really Need a Heater?

Here’s how average aquarium temps stack up indoors:

So while our climate keeps most tanks warm naturally, there are situations where a heater becomes essential:

💡 Pro Tip: Sudden drops in water temperature stress fish and suppress their immune systems—making them vulnerable to diseases like ICH (Ichthyophthirius multifiliis).

Heaters in Disease Treatment: The ICH Case

Let’s talk about white spot disease, a.k.a. ICH.
This common parasite thrives when fish are stressed—and temperature swings are a top trigger.

Here’s how your heater helps fight ICH:

🚨 How ICH Works:

ICH has a life cycle: it attaches to the fish, drops off to multiply, then swims freely to find a new host.
Most medications only work during the free-swimming stage—so speeding up the life cycle helps eliminate it faster.

🔥 The Treatment Strategy:

Gradually raise the water temperature to 31°C (maximum).
This shortens ICH’s life cycle, increasing medication effectiveness.
For larger or more sensitive fish, always raise the temp slowly to avoid thermal shock.

⚠️ Watch the Oxygen!

Warmer water holds less dissolved oxygen.
At 31°C, your fish may struggle to breathe—especially bigger species.

💡 Play it safe: Always add an air pump or increase surface agitation to keep oxygen levels up during heat treatment. Don’t treat temperature like a cure-all—it’s one piece of the puzzle.

Heater Wattage: Choosing the Right Power

Yes, heater wattage matters—a lot. Too little and the tank won’t heat. Too much and… well, you might cook your fish. 😬

Here’s a quick wattage guide:

⚠️ Never use a 100W heater in a 10L tank—the risk of overheating (and killing your fish) is extremely high.

💡 Pro Tip: For large tanks, use two smaller heaters instead of one big one. That way, if one fails, the other keeps things stable until you notice.

Heater Placement & Safety Tips

Every tank layout is unique, and heater placement matters for even heat distribution. Here’s how to do it right:

✅ Place the heater near a filter outlet or water flow for consistent circulation.

✅ For large tanks, place two heaters at opposite ends.

📹 Need help? Take a video of your tank setup and bring it to our store—our team will recommend the best heater type, placement, and backup strategy.

Safety First: Common Heater Mistakes to Avoid

🔥 Use a heater guard
Protect your fish from accidentally touching the hot surface—especially curious species like plecos or bichirs.

🧯 Switch off your glass heater during water changes
Water change = lowered water level. If the heater remains on, it can overheat and crack, which can lead to electric shock or even harm your fish.

💦 Never change too much water at once
A drastic temp drop can shock your fish—keep water changes gradual to avoid stress.

⚠️ Danger alert: A running glass heater exposed to air can shatter. Always unplug it before maintenance!

Recap: Key Takeaways

✅ Heaters aren’t always needed—but when they are, they’re critical.

✅ Use them in aircon environments, during rainy season, or for heat-loving species.

✅ ICH treatment relies on temperature to work—raise slowly, pair with medication, and boost oxygen.

✅ Choose the right wattage for your tank size—too strong = dangerous.

✅ Use two heaters for big tanks to build redundancy.

✅ Always switch off your heater during water changes, and use a heater guard for safety.

✅ Not sure what’s right? Our team is here to help—just bring a video of your setup.

Need Help or Custom Advice?

Still unsure which heater suits your tank, or how to place it for even heating? Need support for ICH treatment? Just visit any of our stores or send us a video of your setup—our aquarists will guide you through every step.

👉 Next Up: Acclimating New Fishes to Their New Homes

🐡 Puffed up with knowledge? Give us a like and keep floating along!

Proudly presented by our That Aquarium Digital Team, where innovation meets aquatic excellence.

Published on 13 June 2025

Author: Kelvin Phua

Illustrator(s): Chai Minyu, Abbie Tan