NICREW Mini Aquarium Betta Heater, 15/25/35/50/75W Fish Tank Heater, 15 Watts, 2.5 Gallons

I use these to warm the water in my Aerogarden to speed up and improve germination success. Worked well. Seeds 98% germination rate and seeds sprouted 1 week faster. That is important here as the growing season is so short that any jump start is crucial for a bountiful harvest.

CLIFF NOTE VERSION: Both heater work very well. The Nicrew is smaller, less obtrusive, but not adjustable. The Hygger is a tad larger, is adjustable, and has a large red LED readout of the tank temperature.LONG VERSION: I have purchased mini-heaters in the past and they either didn't heat or fried the water. I long ago learned to do the bucket test. I purchased the Nicrew Mini (15 watt) and the Hygger (15 watt). The Nicrew is smaller with a preset stated as 76 degrees F. The Hyger is adjustable with a large LED readout. Both were placed in a 3 gallon bucket of 70 degree water for one hour before plugging in. This is a manufacturer suggestion, and, IMHO, failing to do this is bad for the heater. The room was 70 degrees. I plugged them in and set the Hygger. An hour later both buckets of water were at 74-75. That temp held for 24 hours, even though the room temp dropped to 65 at night. I'm now using the Nicrew 15 watt in a 2.5 gallon tank and I’ve very happy with it. The Nicrew holds rock steady at 74. I'm keeping both heaters. I'll use the Hygger in the winter when the room temp is much colder and I may need to use the adjustable feature to compensate for the room/tank temps. I used a scientific thermometer for my readings. The Nicrew is preset at 76, and my reading is 74. Since the temperature remains steady, I feel that 1 to 2 degrees difference is acceptable.

I've had this heater in service for a while now. It's appearance is fairly non-intrusive although it shows up a bit larger than I thought it would in a 2.5 gallon aquarium. This heater has a red light when it's on and a green light when it's off. I would say this heater doesn't use a lot of power because it doesn't come on very often. It will keep the aquarium at around 75° to 76°F but that's about as much as it will do because it simply doesn't cycle on often enough to heat the water any warmer than that. That's okay but I would have preferred 78°F since Bettas enjoy their heaters. And the Betta does enjoy hovering just above this heater. This is an okay heater for a 2.5 gallon aquarium but I would not recommend it for any larger size tank. This little heater does heat but it doesn't come on quite often enough.

It is really difficult to hide the "logistics" in a 5.5 gallon aquarium. This compact heater and a single sponge filter worked perfectly for me.I put the sponge filter and the 50 watt heater in one corner and planted rotala beside and in front of the duo. The logistics/mechanics are pretty much invisible.Note: I tried the 35 watt heater and found it to be under powered. The exchange for the 50 watt went very smoothly.

Sadly, less than a year of having this product, it has stopped working.The light remains green, how ever my thermometer reads way below desirable temperature for my poor betta.

I’ve purchased the 15 watts before for my smaller tank and it works perfectly. You can tell by just feeling the glass that it’s warm and my betta is lively and comfortable. She even likes to sleep in between the heater (without getting stuck, she’s on the smaller side so please be wary your betta may try to explore and go behind the heater as well!)Now for my 5.5g tank I purchased the 35 watts. Thought I’d give it some time but nope, water is still very cold. Don’t know if it’s just the 35 watts model but I’ll definitely have to purchase another brand for this tank. Sucks!

I have a 5 gallon shallow nano tank (height is 7 inches). Its tough to find a sleek, unobtrusive heater that doesn't look like a submarine or telescope totally ruining the effect of my aqua-scaping. This tank is more of a planted tank, with one betta and will soon have a few shrimp and otos. This one works for a number of reasons. Its small and is a slim rectangular shape without brand-lettering or silver tags to make it stick out. The cord is pliable and long enough exiting the tank. It fits the height of my shallow tank with a few inches to spare and the suction cups are very secure and won't pull off when you take it out to clean. It does have a red light to tell you its heating, but thankfully not distracting and in your face (its very tiny and its placed on the top of the unit along with a green light to let you know when its running at 77 degrees. This is very nice and minimalistic. I have checked the water temp several times now with a TDS meter and a traditional glass thermometer and it is consistently 77 to 78 degrees. Very happy with it. Also bought a 35 watt for a different smaller tank. Same results. Definitely worth the price.

The media could not be loaded. This little heater works just as intended and even better! It doesnt require a lot of set ups as you just plug it in and it does everything for you. I have seen that sometimes one of the suction cups do comes loose once in a while. It might be my fishes, for that I recommend sticking the heater to a dry part of the fish tank wall (above the water) and then sliding it down to the preferred height.