NICREW Aquarium Internal Filter, Submersible Power Filter with Multiple Function for Fish Tanks 2 to 5 Gallon, 40 GPH, 3.5W

I bought this product, but when I used it for the first time, it didn't work. What a waste of money. I wish the seller would give me a replacement. 😢😢

Works fine. Quiet. A little too powerful for my 3 gallon tank but I was able to diffuse the output so our Betta can still enjoy his home.

I’ve been using this small internal filter for a few weeks in my 5 gallons tank and it does a good job. It’s compact and easy to set up, and doesn’t take up too much space inside my aquarium. The flow is gentle enough for my fishes but still keeps the water moving and super clear. It runs pretty quietly too, which is a big plus, but it is not completely silent either. The only thing to note is that you’ll need to clean the sponge fairly often since it’s small, but that’s expected with a filter this size. Overall, it’s a reliable little filter for small tanks. Great value for money.

I bought this filter in June 2025, and this filter works fantastic so far for my 5 gallon betta tank (I got the mini filter 3.5w)! The tank stays very clean and oxygenized without stressing my betta out, since the waterfall-like option gives a gentle, not overly disruptive water flow that I can adjust the position as needed. My old filter that came with the tank I found was too stressful and my late betta had a hard time swimming through, but my current betta seems to swim around this one with ease. I do have the water flow streaming onto a rock which helps too (see pic). It's very easy to set up as you just put it together and plug it in, no additional pumps required. Overall, this filter is way cheaper than my local pet stores and works much better without being overpowering for my betta. If it were to break, I would definitely buy this again.

Just set up but seems to be working well! Strong flow and quiet!

Edit from 2 stars to 3: The maker contacted me to tell me I would get a full refund and apologized that it wasn't working. But I needed to send a video and take the whole thing apart! Super inconvenient. Turns out it was "airlocked", I had to flip it upside down to get the water moving, then put it back right side up and it was good to go after that. Old: Worked great at first, but within 2 months it was dead. It's also very strong... so for a small tank, the water it pumps back out, comes out at MACH SPEED! sent my fish flying a few times across the tank.