Marina Submersible Aquarium Heater, Betta Fish Tank Heater, 25-Watt, 11230, Black

I have multiple smaller tanks for keeping/breeding bettas and they’re in a spot in my home where temperatures fluctuate so tank heaters are used, these are great submersible heaters and work fantastic in my tanks that are 2, 5 & 10 gallons.

I've had this for 3 months in my 2.5gal betta tank and it's perfect. Small with an adjustable temperature, plus a little light turns on when it is heating. It's fully submersible and if you aren't sure if it will heat to the correct temperature, take 5 seconds and research how to calibrate aquarium heaters. Calibration takes about 10min, you basically stick it in the water unplugged for a short time and then you turn it on. That way you can make sure it's sensing the initial temperature correctly. The only reason I gave it four stars is because I wish the dial was numbered, but everything from ordering to shipping to usage has been perfect. Make sure you also have a thermometer in the tank, they're like $2 and will save you from ever worrying if your tank is too hot or cold. If you are debating whether to get this or a non adjustable heater, GO WITH ADJUSTABLE.

The thing I like the most about this heater is the temperature is adjustable. I bought one to try out in my 5 gal tank and it works very well. So I bought another one to try in my 2 gal tank and it works very well too. I am going to buy another one for my 3 gal tank. My betta fish love it. The thing I like the least is I have to use the thermometer to monitor the water temperature and adjust the heater accordingly. But even the very expensive heater that I use in my 75 and 34 gal tanks which comes with the temperature indicators/marks I still have to do the same thing to monitor the water temperature because the heater temperature indicator is just a reference. So I have no complain against this little handsome guy.

I purchased this for a 3 gallon betta tank. At first it took me a while to get the hang of it and it’s settings. It does heat and when the highest setting is set it heats to the highest temperature to about 76 degrees Fahrenheit in a 60-65 degree home (when the House heater is not on). The thing is that it doesn’t keep the temperature constant. It heats up for a couple of hours and then it like turns off but the light is still on and it drops the temperature in the water for a few hours and it turns on again for a few hours and so on...Maybe because I live in a cooler area it drops but I’m not sure I’ll have to try other heaters with higher watts. I guess it would be good for areas that are not that cold or when the season changes to a warmer weather in the day and it’s somewhat cold at night.UPDATE: after two and a half month of use it just stopped working. I won’t be buying this brand of heater again it plays too much with the temperature it never goes up 76 and when it turns off it drops the temp way down. Just invest in a better heater.

I was looking for a compact aquarium heater to fit into the filter outflow compartment of my Fluval Spec V tank (5 gallons), so it wouldn't be visible in the main body of the aquarium, but my choices seemed like either the non-adjustable, black plastic encased Fluval/Marina for $22-25, a $20 Hydor heater with no protection on the body of the heater, or a $28 EHEIM. If money was no object, I'd have gone with the EHEIM with its superior reviews and reputation, but I didn't want to spend that much and decided to give this Fluval Marina heater a try. I've only had it in the tank for about 10 days, but so far I like it.PROS:- Price - very reasonable, half the price of the better/more expensive heaters, at fourteen bucks- Compact size - easily fits in my Fluval tank's filter compartment- Adjustable temperature for the price of a fixed temperature unit- Plastic bumper on bottom of the glass barrel protects the heater from impact.- Heats a 5 gallon tank up to 76*F, might do 78 if I twisted the temperature knob all the way to the right.CONS:- Unknown reliability. So far, so good, but a few weeks is too little time to tell. I'll come back in a year or so (hopefully not earlier with bad news) and update.- The heater is just adequate to heat my 5 gallon tank to the lower end of typical tropical fish temperatures. I would not think of using this in any tank over 6 gallons, but then again, it's only designed for up to 5.5 gal tanks.CONCLUSION:So far, this heater appears to be exactly what I wanted. It fits my Fluval Spec V perfectly and does the job it's supposed to do. I've got no real criticisms, so it gets 5/5 stars until/unless my experiences change (hopefully they won't).

After looking through my order history I realized I’ve ordered 13 of these because I loved them so much at first. I have a lot of betta, dwarf frogs, shrimp, and dwarf crayfish tanks between 2.5 and 5 gallons and these were the perfect size. I never had problems with keeping the temperature within a good and consistent range until recently. I loved that they were adjustable so you could use them for all different fish and their temperature preferences. I’m so sad to say that they have all stopped working after about 6 months. All of a sudden my tanks temperatures are colder every day and of course just in time for winter :( Now time to rush to get all new heaters for my tanks. I loved them so much I just wish they lasted longer!

Heater works great! I’ve had it over a month now, and I’ve had no problems! Water stays around 80! Definitely worth being a little more than the cheaper heaters. I can’t risk my betta dying because of insufficient temp control while I’m away from home.Only weird thing is that you can’t see what temperature you are setting it to, but I started it low and slowly turned it up over a day or so until the temp reached 80 and stayed there.Racs (my betta) loves this heater most importantly! He cuddles up to it like it’s a blanket!Reliable heaters like this one are so important for tropical fish health. I’ve never had a heater before for a betta because I didn’t realize how bad temperature fluctuations of day and night were for Bettas until now. Seeing how much healthier this fish is compared to fishes without the heater really convinced me.

Funciona muy bien y a la tortuga de mi hermana parece encantarle. Se pasa buena parte del día encima, sobre todo cuando quiere dormir. Tiene regulador de temperatura por lo que no hay problema de que la tortuga se cueza.

Tenis mis dudas por la potencia para un acuario de 10 l, pero después de 6 meses hace su función perfectamente.

The heater has no way to know what temp it is at due to no markings on the turn nob on the top like most others have.

Calienta un tanque grande

Perfetto