Why You’ll Love It
hygger Aquarium Hang-On Back Filter is a small waterfall filtration system with a surface skimmer to adjust water flow, and it works quietly for fish tanks 1-20 gallons. It pumps water up and forms a waterfall to improve oxygenation, with adjustable flow & oily film remover to clear surface oil and floating debris. The 4.5W & 5.5W models are designed for frameless fish tanks and fish tank thicknesses between 0.2 in (5 mm) and 0.59 in (15 mm). The 3.5W model is suitable for frameless fish tanks and fish tank thicknesses within 0.2 in (5 mm). 
Key Features
Powerful Filter System
The hanging aquarium filter is powerful and energy-saving, providing filtration, circulation, and oxygenation 3-in-1. It can not only effectively filter impurities and debris in water, but also add air bubbles into water to increase oxygen while the water circulates. It is equipped with an oil film valve to remove the float and oil film on the surface of the fish tank.

Energy-Efficient HOB Filter
hygger 238 hang-on back aquarium filter provides stable output while saving energy. It delivers adjustable water flow and reduces the water flow for low-flow-demand fish without affecting the filtration efficiency.

Washable & Replaceable Bio Sponges
The HG238 has a replaceable bio sponge. The activated carbon and biochemical cotton feature a high density and are not easy to clog or damage. It can efficiently filter out impurities, such as residues and feces.

Quiet Hanging Aquarium Filter
The waterfall at the outlet makes water flow gently and smoothly; its working sound is ≤35 dB. It is quiet and will not disturb daily life.
Usage Tips
- Before the first use, it is recommended to fill the filter with water, fish tank water level must be above or the same height as the water inlet of the surface skimmer, then power it on. It will gradually release air and draw water up within 1 to 2 minutes.
- Recommended to clean once a week for a better filtration effect.
Specification

Package:
1 x Water pump inlet
1 x Tee Connector
1 x Adjustment knob (rotational speed control)
1 x Straight-through Connector
1 x Extendable Tube (not for 3.5W model)
1 x Inlet Sponge
1 x Adjustable Knob
1 x Skimmer Basket
1 x L-shape Connector
1 x User manual














This filter works amazingly well on my betta’s 10 gallon. I purchased it mainly for the adjustable flow but I’ve been surprised by how much the built in skimmer helps keep the tank clean!
Nice size, easy to modify. Nicking it a bit for poor instructions, and tiny print requiring a magnifier.
This is a great filter! It includes adjustable flow, a skimmer intake, foam intake pre-filter, and allows lots of options for filter media customization. Not to mention it is really quiet.
Easy to assemble and very quiet motor!! Love it 😊
It works well for me..
Pretty good filter. This filter works well. Have it on my 10 gallon and so far so good. I like that you can adjust the flow.