Hydor Micro & Mini Aquarium Slim Heater

By Hydor
Rated 3.8788 out of 5 stars


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Selected: Size:

$15.45Chewy Price

In Stock
FREE 1-3 day delivery over $35

About This Item


  • Specially designed for micro tanks and mini aquariums.
  • Helps maintain the ideal temperature and natural warmth that fish like guppies and bettas need.
  • Simply plug in the heater, no complicated set up.
  • Shock-proof design and the ability to run safely when dry.
  • 7.5 W heater measures 5-1/2" x 2-1/2" and heats 2 to 5 gallons of water.

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Fish TypeMarine Fish, Marine InvertebrateMarine Fish, Tropical FreshwaterBetta, Cichlid, Goldfish, Marine Fish, Tropical FreshwaterMarine Fish, Tropical FreshwaterBetta, Marine Fish, Tropical Freshwater
Aquarium TypeFreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterFreshwater
Capacity (Max)2-gal

Questions & Answers

8 Customer Questions

Does this have a thermostat that will help it turn on and off or is this an "always on" heater?
Answer by ChewySep 02, 2017
This heater is always on when it's plugged in and should always be used with a thermometer. If the water temperature should exceed 75° F (24° C), unplug the heater.

Cam I use it underneath the fish bowl, meaning OUTSIDE of it?
Answer by ChewyDec 21, 2018
This is intended to be submerged in an aquarium.

Why can't I keep it under a light I keep on 24/7?
Answer by ChewyJul 05, 2018
The Mini Heater should not be used in aquariums positioned close to air conditioning outlets, in direct sunlight, near sources of heat, or under a source of light that is kept on for long periods of time. This can alter the temperature of the heater.

Can this heater be used safely in a 3 gallon plastic tank? The tank is about 3 cm of thick plastic?
Answer by ChewyFeb 14, 2018
In dry conditions, the heater reaches temperatures of about 176°F, and this may cause serious damage to plant and animal life, as well, of course, as to plastic tanks and bowls.

ReviewsWrite a Review

Rated 3.8788 out of 5 stars
33 Ratings
Would recommend to a friend

33 Customer Reviews

Rated 2 out of 5 stars
By Sarah on Dec 28, 2018

Didn't hear my tank as I thought it would

I have a 1.5 -2 gallon tank with a beta fish and for how this heater is rated for bigger tanks it barely brought my tank up to a Luke warm temperature and if this can be used on bigger tanks I don't see how it can heat the water appropriately wen it barely warms my little tank I'm kind of sorry I bought this product but nothing I can do now

Rated 3 out of 5 stars
By Macey on Dec 21, 2018

Hydor Micro & Mini Aquarium Slim Heater

I'm not sure if there was something wrong with the one I received but it doesn't work at all. I've had it plugged in for over 12 hours and the water hasn't gotten any warmer.

Rated 5 out of 5 stars
By blank on Feb 2, 2019

awesome for small fish tanks

it works like a charm and my tank heated up in no time. I would definitely recommend.

Rated 5 out of 5 stars
By Sara on Sep 8, 2018

He loves it!

Since we got this heater, Squidward the Betta fish is so much more active.

Rated 4 out of 5 stars
By Tamann on Jun 24, 2018

Good product

It's working very well. I have a 5.5 gallon fish tank. It works perfect for my small tank.

Rated 4 out of 5 stars
By Cassy on Jun 11, 2018

Good for the price

This heats my 3 gallon tank very well. The only thing I don’t like is that there’s no stopping point for the heat level. When I first put it in and came home from work, my fish tank was at 85 degrees and I normally keep it around 78. The fish were fine but it frightened me a bit to realize it could potentially have been bad.

Rated 4 out of 5 stars
By Kendra on Apr 1, 2018

Decent heater

This is a decent heater for very small tanks. Not good for anything more than 2 gallons but good for small betta tanks.

Rated 5 out of 5 stars
By Fishtank18 on Mar 19, 2018

Working, No issues

Seems to be working so far, I've had it plugged in for a few days now, temperature fluctuates between 80-81 degrees in 8 gallon tank with no other heat source.

Rated 2 out of 5 stars
By DebiGag on Feb 27, 2018

Doesn't do what it claims

This heater claims that it will keep your tank water at about 6-7 degrees warmer than the room temperature. NOT. My house stays around 68 degrees and the tank stays around 70-71. Waste of money. Need to go buy a "regular" adjustable heater.

Rated 5 out of 5 stars
By Stevue on Feb 13, 2018

Heats Up My Bettas Water Excellent

This heater helps a lot after about an hour or less, it heated up my tank to about 78 degrees it is really quick and efficient.