If you’ve been considering entering the world of fish or shrimp breeding, or even raising invertebrates like amphipods and copepods for aquarium food, then you likely have been reading about refugiums. Refugiums allow for tank water to flow through while protecting sick or weak fish, as well as fish that are at risk of predation in the tank, like fry and shrimplets.
Refugiums are a great option for quarantine and breeding, and some can even be used as part of a sump setup. It can be overwhelming and confusing to learn about refugiums, though, so we’ve put together reviews of the six best hang on back refugiums for your aquarium.
Table of contents
- A Quick Comparison of Our Favorites
- The 6 Best Hang on Back (HOB) Refugiums – Reviews 2021
- Buyer’s Guide
A Quick Comparison of Our Favorites
|Best Overall||Finnex External Refugium Hang-On Box||
|Best Value||Fluval Hang-On Breeding Box||
|Premium Choice||CPR AquaFuge2 Hang-On Refugium||
|Sudo Starpet Hang-on Breeding Box||
|ISTA IF-648 Hang-On Breeder Box||
The 6 Best Hang on Back (HOB) Refugiums – Reviews 2021
1. Finnex External Refugium Hang-On Box – Best Overall
The Finnex External Refugium Hang-on Box is not just a HOB refugium, making it the best overall HOB refugium pick. It also includes an adjustable water pump and LED light suitable for medium to high light needs. This kit can also be purchased with a light suitable for low lighting needs and without a light.
This HOB refugium measures 10.25 inches by 5.5 inches by 5 inches and is made from sturdy plastic. It includes two leveling knobs that help prevent spills, although overflow is possible if the outlet becomes clogged. This refugium also includes removable baffles to help further reduce the water flow if needed for shrimp, fry, or low-flow fish like bettas. The included water pump can run up to 40 gph.
2. Marina Hang-On Breeding Box – Best Value
The best HOB refugium for the money is the Marina Hang-on Breeding Box. It holds up to ½ gallon of water and includes separators to create up to three chambers. The separators feature slats that are just large enough for fry to pass through to become separated from the mother.
This HOB refugium measures 10.7 inches by 5.8 inches by 5.7 inches and is made from sturdy, transparent plastic. It can be used on rimless aquariums with a minimum glass thickness of 5mm. This HOB refugium includes leveling feet and is available in two smaller sizes as well. It requires the use of an air pump that is not included.
3. CPR AquaFuge2 Hang-On Refugium – Premium Choice
For a premium product pick, take a look at the CPR AquaFuge2 Hang-on Refugium. This product comes in three sizes of sturdy acrylic. They include a black acrylic backing that does not allow for light to pass through to the main tank, making this product a great option as a refugium for plants.
The largest size option of this HOB refugium measures 25.5 inches by 4.5 inches by 12 inches and holds 4.7 gallons of water. This kit includes a powerhead with all three sizes. This product is made with baffles that allow for plants, animals, and substrate in the refugium to remain undisturbed while the water is not allowed to stagnate.
This product does not include a light but does include space above the water line to place one. The baffles in this kit are not removable and it does not have a lid.
4. Sudo Starpet Hang-on Breeding Box
The Sudo Starpet Hang-on Breeding Box is a large, sturdy HOB refugium option. It is nearly identical to the Marina HOB Breeding Box, but at a higher price.
This HOB refugium does not include an air pump or light, although an air pump is required for its use and a light is recommended. This HOB refugium measures 10.7 inches by 5.8 inches by 5.7, is made from sturdy, transparent plastic, and has two leveling knobs. It also includes two separators with slats large enough for fry to pass through but too large for adult fish to pass through. The slats can be used to turn the box into three separate chambers.
5. ISTA IF-648 Hang-On Breeder Box
This HOB refugium measures 10 inches by 5.5 inches by 5.25 inches and holds approximately ½ gallon of water. It has two separators with slats that allow for fry to separate from other fish. You can make up to three chambers with this box. The separators and holders in this product allow for some customization. The box does not include the needed air pump or a light, but it does have a lid. The pump inlet can be loud and may require some adjustments to reduce noise.
6. Blue Ocean REF 15 Hang on Refugium
The Blue Ocean REF 15 Hang on Refugium is a premium-priced HOB refugium made from acrylic. It features a black acrylic back to decrease light leaking into the main tank. It is prone to scratching and pieces may break with rough handling. It is also prone to leaking, so you’ll need to watch for this closely.
This product measures 13.25 inches by 4.75 inches by 12 inches and holds a little more than ½ gallon of water. It does include a filter with a bio sponge intake cover. It does not include a light. If this product chips or cracks, it can be repaired with aquarium-safe epoxy or acrylic. It only has one chamber and does not include baffles.
|When to Use a HOB Refugium||When to Use a Quarantine/Secondary Tank|
|Acclimating new fish and invertebrates that are coming from quarantine||When first bringing new fish and invertebrates home|
|Breeding specific colors or types of shrimp||When attempting to raise or breed shrimp with predatory fish in the main tank|
|Protecting weak or non-contagious sick fish or invertebrates or protecting sensitive plants||While treating fish or invertebrates for a contagious illness|
|Protecting fry from cannibalism or predation in the tank||Raising large numbers of fry or shrimplets|
|Growing chaeto, amphipods, copepods, or other food sources||Growing large amounts of ground cover plants, like mosses, before adding to the main tank|
If you know exactly what you want a HOB refugium for, then these reviews should help you weigh the pros and cons of different products to pick what will best meet your needs. If you aren’t sure what you’re needing, use these reviews to identify what you’re hoping to achieve with your HOB refugium and then pick a product from there.
The Finnex External Refugium Hang-on Box is the best overall HOB refugium pick because it’s a high-quality product that includes everything you need to get a HOB refugium up and running. The CPR Aquafuge2 Hang-on Refugium is the top premium pick because it’s made from high-quality materials and includes a fully functional pump setup. For the best value, the Marina Hang-on Breeding Box is the top pick, because it’s high-quality, cost-effective, and an especially good pick if you already have a pump and light at home.
Picking a HOB refugium is overwhelming and learning everything there is to know about getting a HOB refugium working can be confusing, so use this list of products to help make choosing a product easier so you can focus on how you want to set it up to work best for your tank.