Marina Betta Fish 8W Submersible Heater - For Fish Tank Aquariums up to 1.5 US Gallons (5 L)

I was very iffy about getting a heater for my betta as I did not want to deal with the nightmare of it cooking my betta which I always worried about. I have my betta in a 2 gallon glass bowl and despite keeping him in the warmest room in our house during the winter and the room being very small. Despite all this his water was so chilly and he was very inactive and not eating much (my betta was always very active and very curious and very hungry). I decided I needed to get a heater and this heater being very small (so as to not take up much room) and being specifically for bettas I figured I'd give it a try. The water is now a toasty 79 degrees and my betta is once again very active, very healthy, and his colors are brighter and his fins flaied out. It took him just a few days to perk up and get back to his normal self after putting in the heater. Now, PLEASE READ THE FOLLOWING. These are very important points. 1. Use a thermometer. I used this one: Marina Floating Thermometer with Suction Cup . I got it off amazon and it is small, does not take up much room (just the bottom needs to be subermged) and is accurate. YOU MUST HAVE A THERMOMETER. I highly recommend that one. 2. DO NOT USE THIS IN A 1/2 BOWL. Despite it saying it can be used for this in the directions do NOT use this. It will heat the water up wayyy too much and cook your fish. If you are using a half a gallon bowl I am begging you to please upgrade to at least a one gallon bowl. A betta can barely turn a 360 in a half a gallon bowl and they need exercise to stay healthy and well. I recommend at least a two gallon bowl/tank. They are very cheap off amazon OR go to your local craft store and combined with a coupon you can get a glass bowl in 2 or 3 or 1 gallon for less than 10 dollars (check out michaels!), very cheap and your betta will be much happier and you don't have to worry about the cost. 3. IF you are using a 1 gallon or 1.5 gallon bowl/tank get a wall timer and set it so that it goes on and off every hour (1 hour on 1 off 1 on etc.). It will get too hot if you do not do this. This works perfectly with my 2 gallon bowl/tank and it would work up to a 3 gallon tank/bowl (ignore the directions) but I wouldn't use it for more than 3 gallons. The way you clean it is to soak it for about 15 minutes or more in a mixture of vinegar and water. Do NOT use soap on it or on anything you put in your fish tank. Soap leaves a residue that will make your fish sick. Using a small amount of vinegar and hot water to clean things works well. When you first put the heater in the bowl/tank wait 20 min before turning on to allow the heater to adjust to the current water temperature and make sure when removing it to unplug it and then leave sometime for it to cool off. To be noted it took about 5-6 hours for the heater to bring my 2 gallons of water to its set 79 degrees. I really recommend this heater and it works perfectly for me. The only complaint I would have is that it is a very small heater and $15 is a little pricey. I have gotten heater for 10 gallon tanks for cheaper. Good product.

This heater is excellent! I've used it for 3 months now. I have a 1 gallon tank and it works great with my beta. He loves it and rests atop it whenever he wants to get warmer. ***Important things to know:*** This heater does NOT shut off by itself. It says it will reach a preset temperature, but it means the HEATER will set to a temperature, NOT THE WATER! I learned this from another review. This means your water can get hotter and hotter and boil your fish without supervision! WHAT TO DO: I bought a simple $12 timed plug-in safety outlet that has options for 1 hour, 2 hours, 4 hours, or 8 hours. (Simple Touch C30004 the original Auto Shut-Off Safety Outlet, Multi Setting) You also must buy a thermometer! I bought this little one for $2.50 (Marina Floating Thermometer with Suction Cup). The thermometer has an easy to read green range from 70-80 degrees F, which is safe for most fish. Betas like it closer to 80 degrees. My average room temperature is usually around 72 degrees, and the 4-hour setting on my timed outlet always brings the temperature right up to 80 when I see that it's dropped to around 70. I would NEVER recommend using the 8-hour setting on the outlet, but the 4-hour setting is usually perfect to raise the temperature about 10 degrees, and the 2-hour setting will raise the temperature about 5 degrees. (Adjust depending on your own average room temperature) Together, all three of these things have kept my beta happy, warm, and healthy! The only downside (besides the heater requiring a timed-outlet) would be that I think my beta lost some of his tail due to frequent resting above the heater. He's just fine, but his tail looks kind of torn and I thought it may have been due to the heater. Good luck!

I would have rated this heater 5 stars had the company not put so much thought into a deliberately deceptive, albeit technically accurate description. First, and most important to realize, is that this is an always on heater. It has no thermostat, it simply warms up and stays warm all the time. So the statement that it "reaches a preset temperature" is extremely misleading since most will interpret that to mean the water temperature, when in fact it's the HEATER temperature that remains constant. Whether or not it keeps a bowl/tank at a desired temperature depends on the tank size/water volume, temperature of the room, amount of water circulation/movement, other heat sources such as a light being on or off, lid or no lid, acrylic or glass container, heater placement, and so on. All small "Betta" or "bowl" heaters work this way. This is an 8 watt heater. These heaters usually run between 7.5 to 15 watts. If you have need of the higher wattage, it's much better to use two 7.5 than one 15 watt. That way just one can be unplugged if the water temp is too high, giving you a bit more flexibility. They can be safely buried in the substrate, a nice option in some set-ups. This particular heater has a small red LED, which the description states is lit "when the heater is working" a technically accurate but also deceptive statement. It should more truthfully state that the light is lit whenever the heater is plugged in, rather than give the impression the light, and therefore the heater, will cycle on and off. Rest assured, it won't. No matter the temperature of the water, the heater will emit 8 watts worth of heat anytime it is plugged in. Using this type of heater requires careful and ongoing monitoring. An accurate thermometer is a must. You cannot rely on charts/claims as to how many degrees a specific size heater will raise the temperature in a specific size tank, there are far too many variables. Still, these little units can be quite effective, and I do like this one quite a bit. The LED light, though possibly intended as more a marketing ploy than anything else, is actually a nice feature since there may be times you will unplug the heater and it's easy to forget to reconnect ones with no such indicator. The weight is nice, it tends to stay where it's put, thinner/lighter models are easily displaced. On identical tanks they seem to be very consistent. It is entirely possible to seriously overheat a bowl or small tank using this type of heater. That is not a malfunction, it is simply an inherent risk with any always on heater. If the room gets warmer, the water will as well. These heaters do not adjust for any variable, they simply continue to emit the same amount of heat no matter what. That is what most people having problems with them don't realize, and what the cleverly worded descriptions fail to make clear. When the room temperature changes, so does the tank temperature. These heaters merely keep a small volume of water a few degrees warmer than it would be without it. They do not and cannot maintain any tank at a specific temperature, ignore claims of "maintains ideal temperature" as they are patently false. The aquarist has to be the thermostat by matching tank size to heater size (wattage) and continually monitoring fluctuations due to changing room temperature and other variables. These heaters are not for overly sensitive species, but it is probably far better for a Betta to be in water that fluctuates between 75° and 85° than in unheated water fluctuating between 65° and 75°. Bettas are heat loving fish and quite tolerant of even very high temps, which makes using this type of heater less risky but still not foolproof. For around $20 or more, a heater controller can be attached. I have a rack of 9 identical small tanks w/9 of these heaters connected to one power strip that is plugged into a single controller set at 82°. The probe for the controller is in one of the 9 tanks, and this works fine, keeping all of them a steady 82°. A less expensive solution though somewhat less exact, is to purchase a stand alone *dimmer switch (the type with the plug, about $10). You can then do rather fine adjustments usually with a slide, up or down as the temp fluctuates. I have this heater on a one gallon Marina Cubus with dwarf shrimp and a dimmer and that works well. As I stated at the start, the actual heater is nice quality and has proved quite consistent from one unit to another. It performs exactly as it should, and the limitations are not flaws, just inherent with what it is. I'm not certain why the description only rates this 8 watt heater for up to 1.5 gallon tanks, but it's relatively meaningless in any case. Some of the 7.5 watt models are recommended for tanks "up to 5 gallons" which is no more valid- it depends entirely on the sum of all the variables in each individual situation. My only real problem is with what I consider deliberate marketing tactics meant to mislead a purchaser into believing the product is, or can perform, as something it isn't. A clear explanation of just how the unit really works is needed, especially if the company wants to be held blameless for problems caused by misuse. *If interested, I also review the dimmer switch I use.

My poor little Betta was freezing in his 1/2 gallon glass bowl. I upgraded to a 1 Gal square tank and added this heater. His water is now just a little cooler than luke warm. He is happy, spunky, and even made his bubble nest the day after I placed him in his new and warmer enviornment. It only took about 4 hours to get his water to a consistant temp and it has remained that way. UPDATE: 01/28/13 Well, this heater keeps the water at a nice temp for ME but not my Betta. I only have a 1.5 gal environment for my fish so this heater began to make my fish sick and he almost died. I read on a site that a heater should not be used unless my fish is in a 5 gal or larger tank...oops! I took the heater out just in time to save my beautiful fish. I'm keeping the heater because I will eventually get a larger tank for him. This product did do its job, so it's nice. Better explanation: Sorry, the heater made the water too warm for him. He was in a small environment so he almost got cooked :-( He would lay on top of the heater and he wouldn't move. He lost almost all of his deep red coloring, he became really pale. A day and a half after I removed the heater he started moving around and by the end of the week his color was back. Over heating the water is all I can figure ?

This little heater is doing a fantastic job in my 1.5 gallon Betta bowl. I read many of the reviews before purchasing this and was surprised that so many said this heater stayed "on" all the time. It DOES NOT stay "On" all the time. Indeed, while the heater is plugged in to an outlet, the red light will be on - because it's plugged in. However, and this is a BIG however, when the heater reaches it's optimum temperature, the unit will stop heating. The red light stays on, but it is not heating. Once the temp drops the heater kicks back on and begins heating again. It's perfect. My little Man-Betta is happy again, swimming and enjoying his plants and leaf hammock. Wish I had bought this sooner :)

I am updating this as of October 5, 2018. I have had this heater for a couple of weeks and like I said previously I read everything in the way of reviews left on this product and to say it's awful is an understatement. I started noticing my betta's fins looking ragged a couple of days ago and ordered a new heater and some medication just in case. Today I pulled the plastic plants from his tank and the rock and noticed a sheen across the top of the water. The dadgum heater is spewing nastiness into the tank, never mind the fact I had to plug in the heater for several hours and then turn it off for several hours. Overnight my little Betta fish drops down to 73*F poor little guy, the up and down cannot be good for it. Now add oil into the tank, this poor fish didn't deserve this, and neither did I. I'm not a fish type person but am genuinely worried for this one, he was beautiful and at $20 a fish he is expensive. I am highly recommending you do not purchase this and find it awful this thing is even sold. BEWARE! Note the photo shows how poorly he is doing since adding the heater and the fuzzy one is taken from the top of the tank looking down on the fish - that is how much oil is on top of the water. Absolutely awful!!!!

I have to agree with most of the reviews that this heater is just ok. I use this heater for a small 1 gallon aquarium with filter for my Betta at work. The man I work for sets the night time temp at work at 62° which leaves the water very cold for my fish. The weekend temps are 62 as well, therefore my fish was freezing. Our winter temps are below freezing and my work is very cold then. This heater always emits the same temp which is ok only during the winter in such a small mini aquarium. In the summer I will not use this heater because then the man I work for leaves the A/C on 84 and it will be fine for him. While I work in the summer the temp at work is set on 77 and it is still ok for the fish without the heater. During the winter my work temp is set on 74 which even is for me too cold. All in all I can only recommend the heater for a very small aquarium in the winter when the heater is set below 72. Also, the suction cup is really awful, it doesn't now stick to anything. I ended up wedging the heater between the wall and the filter system to prevent it from being too lose. Otherwise the heater does do what it is supposed to do.

Works perfectly in my 2.5 gallon fish tank. Temperature reads at a steady 82 degrees, which is fantastic for living in (currently) freezing northern Wisconsin! This heater is a great size for a small tank and it heats your tank up fairly quickly, but I also recommend putting it near your filter so the heat gets distributed evenly. I have had no problems with the suction cup, and mine is submerged about halfway down my tank... it's mostly hidden behind a cave decoration, so it doesn't look too bad either! I didn't think it would work this well, so I'm glad I took a chance and ordered it! I don't have any complaints so far, but if anything arises, I'll be sure to update my review.

I have a blown glass spherical bowl (maybe 1.5 gallon capacity) that my Betta lives in and this little heater is a gem in the winter for him. I have a room on the top floor of a very insulation efficient home & it's warm all year, so keeping my windows open a fair bit is a must even in the winter, which can make for a sluggish and unhappy little guy in the bowl near the window. This heater keeps his tank comfortably warm and himself very happy and active. I've buried it below that gravel however, as it saves a little space, and saves my little guy from getting too close and too hot should he get near it. Recommended for anyone that has a tiny home for their finned friend! Also... in the past, I have tried the flat under-gravel heater, and although it works well, it does not hold up to the test of time and doesn't quite disperse or hold the heat the way that you'd hope it would in a small fish abode. Definitely a must for the cooler months.

Va calentando progresivamente el nanoacuario de mi bettita. Funciona perfectamente, va subiendo un grado cada hora, aproximadamente. Tengo un acuario de 3,4l y me va genial, puesto que es pra acuarios de entre 2l y 5l

Got Defective Product. The seal on Packet was not intact. Getting bad odour from packet. No Response from Amazon Customer Care.

I disliked the two pronged plug but everything else is top class small compact just right for my betta show tanks

Top fonctionnement pour mon combattant qui à une eau toujours à bonne température ce qui permet à mon combattant d'avoir ses couleurs magnifiques