hygger Small Aquarium Betta Heater, Submersible Fish Tank Heater 10W/25W/50W/100W with LED Digital Display, Suitable for Marine Saltwater and Freshwater up to 5/10/16/26 Gallon

I needed a heater I could adjust for a 2 gallon betta tank. It’s been cycling for a couple weeks with guppies until the betta moves in. Last weekend the water got too warm because the weather was hot and the heater I was using doesn’t have a thermostat. This little Hygger 10 watt heater is perfect!1) the heater is small in size for the tiny tank.2) it is thermostatically controlled3) it is very easy to adjust with the external gizmo on the wire.In the photo the heater is near the bottom of the tank, near unseen behind a ceramic pagoda. This little heater has all the bells and whistles heaters for big tanks have!

Small and effective aquarium heater. It is nice to have a set temp that the tank won’t go below. I use a separate fan to cool as needed.

This heater has been great! Has been consistently within 1 degree of the set temperature and fits great in my smaller tank.

I bought this for its small size to use in a small hospital tank. When I first turned it on, it got up to temp fairly fast but when I stuck my hand in the tank much of the water was still cold. I gave it a good stir and then all was well. It seemed like it thought it had reached temp because the water immediately around the heater was warm so it was holding steady there. This might only be an issue on tanks with no circulation. Once I manually circulated the water it did great and held temp nicely. The temp is matching my floating thermometer within a degree or so. I would recommend primarily due to its small size.

Heat timing is terrible!I bought a 2.5 gallon tank and heater from the local aquarium with a heater that was pre-set at 78 degrees. My betta fish like the tank to be about 79-80 degrees so I bought the hygger tank heater because it allows for heat adjustments.Keep in mind, my tank was ALREADY at 78 degrees when I put the hygger heater in. How hard could it be to jack up the heat by ONE degree?? Apparently, very hard.I took out the old heater, put the new hygger heater in, and set the temperature for 79. Unfortunately, the hygger STARTS at 62 degrees and works its way up to the desired temperature. That's crazy!! Why doesn't it automatically start at 78 like every other preset heater??? 19 hours later, and my tank is still only at 78 degrees.Nowhere on the box or in the instructions does it say that the heater starts at 62 degrees or that it takes a full day (maybe more...who knows??!) to get it up to the desired temperature. I thought about leaving the other heater in the tank while I waited for the hygger to finally kick in, but I didn't want the hygger to detect warmer water and stop working (as the directions say it will do), and I didn't want to risk over heating my fish.Overall, just really poor directions and a total lack of communication on how slowly the heater would reach 79 degrees.My poor betta fish is doing fine so far but I feel bad for him having been so stressed.

It's perfect for a twenty gallon aquarium.

This is a nice little heater. The digital readout is brigh and easy to read. It seems to be pretty accurate as it reads the same as the alcohol thermometer that I put in with it. My only complaint is that the readout & temp module is on the wrong end of the power cord. It is much closer to the plug end rather than the aquarium end so that if you want the readout near the aquarium, chances are there won’t be enough cord length to reach an outlet.

I was skeptical but I was setting up a 2.5 gallon tank intended to be an isolation tank and I didn’t want to consume a bunch of space using a traditional heater. This little unit brought the tank up to 78 in a hurry and every time I check it the temperature is spot on. I didn’t have confidence the suction cup was going to hold but it has been almost 2 months and it hasn’t budged.The control box is almost as big as the heater in length but it can be tucked behind the tank no problem. Setting the temperature is easy. One thing I have not tested is a power failure situation, but I assume it will resume with the previous set temperature.