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Cobalt Aquatics Neo-Therm Aquarium Water Heater

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Submersible Water Aquarium Heater

When you’re installing your Cobalt Aquatics underwater heater, the ultra-flat design makes it simple to hide nearly anywhere in your tank. Some of its best features include:

  • Shatterproof Outer Casing for Extra Protection
  • Microprocessor-Controlled Thermostat for Better Accuracy
  • One-Touch Setting & Adjustment
  • Simultaneous Displays of Set & Current Temperature
  • Easy to Read Multi-Color LED Screen
  • Removable Suction Cup Mounting Bracket for Quick Installation

It can maintain the temperature of your water to within ±0.5 degrees Fahrenheit! This aquarium water heater has a range between 66-96 degrees Fahrenheit today.

Extra Safety Features

You want a safe aquascape for all your fish and plants, and the Cobalt underwater heater delivers it. It comes with thermal protection circuitry that automatically cuts power to prevent any damage from overheating. There is also an audible alarm that sounds in case the tank temperature gets too high. If it exceeds your set temperature, you’ll know it!

Power Maximum Aquarium Size Size
50 W 4 - 10 Gallons 6.5" x 2" x 1"
100 W 16 - 24 Gallons 9.75" x 2" x 1"
150 W Up to 40 Gallons 10.88" x 2" x 1"
200 W Up to 55 Gallons 10.88" x 2" x 1"
300 W Up to 300 Gallons 10.88" x 2.13" x 0.8"


Swap out your current aquarium water heater with a more effective, efficient product. Order your own Cobalt heater and get free shipping!

Reviews (8)

  • 5
    Cobalt heater

    Posted by Ben Wouters on 30 Aug 2021

    Very nice and thin heater. Has been maintaining my desired exactly.

  • 5
    cobalt flat heater

    Posted by james robertson on 19 Aug 2021

    wow, best heater I have come across

  • 5
    Cobalt Aquatics Neotherm aquarium heater

    Posted by Denise Angel on 19 Apr 2021

    This aquarium heater is the best heater I’ve ever used. Keeps consistent water temperature within about .6 degrees. It’s also very easy to change the temperature desired with the easy to use button on top of the heater. No more using a difficult to turn dial like other heaters use. I also like that it’s not made of glass and it’s flat design is a plus in aquarium placement.

  • 5

    Posted by Lesley Davis on 18 Feb 2021

    I am very satisfied with my recent purchase of 3 Cobalt Neo-Therm aquarium heaters. Due to their sleek, flat design and ease of operation, they are one of the BEST heaters available. To adjust the temperature, you simply click the button on top of the heater, which is easy to access WITHOUT having to take it out of the water. It can easily be hidden by tall aquarium plants due to the fact that it hangs vertically in the tank, which is very appealing to the aquascaper. Despite the high price, I feel that these heaters are good investment, and hope they will last for many years!

  • 5
    Cool heater!

    Posted by Allie Greenwell on 4 Jan 2021

    Great heater! So far so good!

  • 4
    Aquarium heater

    Posted by Joe Traina on 12 Dec 2020

    I am, so far, happy with this product. I am a little disheartened though at the way it was packed. A $90 heater! It was thrown i the delivery box and was obviously knocked around quite a bit. I thought it was a return that was shipped to me. The box was a mess. I was considering sending it back, but the unit was intact and the electrical wire appeared to be not to have been unravilled, so I took a chance. Sorry, I think $90 is a bit expensive to be handled so negligently. May not be a lot of money to someone else, but it is to me.

  • 5
    Most Consistent Heater

    Posted by Brittany B on 30 Apr 2020

    My reef tank has never been at a more consistent temp than with this heater. I had read a lot of reviews but I’ve had this heater for about 2 weeks not and my temp has even fluctuated a degree. Consistent 79.2. I run a 13.5gal and the 75watt is perfect.

  • 5
    Cobalt Neotherm Heater

    Posted by Suzan Garau on 15 Jan 2020

    I have become a huge fan of this new aquarium heater and have replaced all my others. I have lost fish when the glass tube heaters inevitably fail and overheat or stop working. These keep my tanks at a steady temperature, and their slim flat shape and black color look great in the tank. Modern Aquarium got my order to me quickly and safely.