NICREW Slim Aquarium Filter, Quiet Fish Tank HOB Filters for up to 5 Gallon Aquariums, Adjustable Flow, 42 GPH, 3W

It's insanely hard to find a tiny HOB (hang on back) filter, especially one with flow control. I have a sponge filter in my 5.5 gallon, but I wanted a bit of flow without my sand being disturbed and this is absolutely perfect! I also love that it already comes with a tiny protector sponge on the intake (something I do with all my HOB filters for fish safety). It's even small enough to fit with my lid. Super quiet which is great because the tank its on is in my bird room. The price is fantastic in my opinion for what this is as well. I'll be ordering again for other small tanks in the future! Highly recommend

Really love this filter! I bought it because I’d read somebody else claim it’s very quiet, and it is. You can hardly hear it running. It does a great job considering its size. I have the filter running on my 4 gal cube & it seems like the perfect amount of flow, but there’s a knob if you find it’s too much/little. I also love the built in motor style, because it feels like much less of a risk for spillage. I was impressed with the quality and thoughtfulness of this design, especially considering it’s only ~$10.

I love this filter. I have a small 4 gallon tank I use to keep my classroom fish during long breaks. It came with a bubbler type filter but it leaked and made a lot of noise. Not to mention the tank needed frequent water changes. This cleared my tank, is very quiet, and fits perfectly on the back of my small tank.

I don't normally write a bad product review. Normally, I just don't buy from the same company ever again. However, I think that this should be under the reviews so that people know. I ordered this item and at time of review, have had this hang on the back filter for 2-3 weeks or so. I woke up and checked and checked on my aquarium only to find water all over my hardwood floor and about 2 gallons of water missing from my tank. I look all over for the source as the water wasn't on the side of the tank or on the sides of the filter. I finally found a constant stream of water running down the electrical cord that runs the HOB filter. Luckily for me, I take precautions and there was no water near my plug. It was leaking where the cord meets the pump at the box of the filter. Buyer beware!! If you don't use drip cords or keep your plug at a higher location, this could be dangerous. If I was less competent this could have caused a fire. I would suggest this product to no one. It only got 1 star because I can't give 0 stars.

Still working after year and a half!It works great for my tank!!

This small filter was perfect for my 3 gallon shrimp tank. Adjustable flow is just right for a nano tank. Had trouble finding one. Glad this came out!Thanks!

It works fine with a 7 inch diameter glass cylinder.

I am giving it three stars because it was a very quiet filter with minimum water disturbance, which is great for a betta, however it was not appropriate for 5 gallons. after two days, my tank was a mess and had to remove it and put a more powerful filter on. I would think it would be OK in a 1 to 2 gallon aquarium but no more.