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Fluval Multi-Chamber Holding and Breeding Box, Large – Up To 3 Separate Housing Compartments



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  • Compatible with Most Aquariums: Easily attaching to the side of most aquariums up to 1” thick, the Multi-Chamber Holding & Breeding Box provides up to 3 separate compartments for protecting fry, sick/weak fish or new fish that require acclimation.
  • Required Parts: Please note that this multi-chamber will require an Air Pump (1 L/per minute) and Airline Tubing, both of which are sold separately.
  • Usage: Ideal as a hatchery and incubator to help protect newborn fry from being eaten (which improves survival rate). Provides a safe haven for injured or weak fish. Helps acclimate new fish as water circulates from the aquarium
  • Space-Saving: This chamber’s design measures 10.25″ L x 5.5″ W x 4.75″ H (26 x 14 x 12 cm) and holds 0.5 US Gal (1.9 L) of water. Hangs onto aquarium exterior for easily observing fish and convenient maintenance.
  • Versatile: Utilizes the same conditioned water as your aquarium, no additional heater or filter required. Can be used with fresh and saltwater aquariums.

Specification: Fluval Multi-Chamber Holding and Breeding Box, Large – Up To 3 Separate Housing Compartments

Item Weight

1.2 Pounds


Rolf C. Hagen (USA) Corp.

Item model number


Date First Available

September 21, 2011

Item Package Dimensions L x W x H

10.55 x 5.91 x 5.39 inches

Item Dimensions LxWxH

5.8 x 10.7 x 5.7 inches

Brand Name


Target Audience Keyword

fish;algae-eaters, betta-fish, bottom-feeder-fish, cichlid-fish, goldfish, invertebrate-fish, mollusks, octopuses, rays, sharks, snails, fish


Follow individual packaging instructions.

Model Name

Fluval Multi-Chamber Holding and Breeding Box, Large





Age Range Description

All Life Stages

Number of Items




Included Components

All items listed in description.

Specific Uses for Product


5 reviews for Fluval Multi-Chamber Holding and Breeding Box, Large – Up To 3 Separate Housing Compartments

4.8 out of 5
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  1. Melissa Pressley

    Bought this breeding box to pair certain guppies, shrimp, snails, etc. mainly for initial pairing since there’s not spots for baby fish, shrimp, etc to hide. I like that it hangs off the front/side of the tank and it’s much easier to work with than most other breeder tanks.
    I’d recommend getting live plants inside the tank to transfer any babies so they can hide there
    Is a great show tank for when you need to get pictures, and a great medical tank for helping introduce new fish or tank care of sick ones.

    ( I’ve tried other brands that have an insert that helps separate the babies so they don’t get eaten, but it’s held onto the tank with suction cups that constantly make it fall off)

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  2. Analise

    I’m so glad i found this! We have 2 set up to temporarily house axolotl larvae. It keeps the water chilled, filtered, and aerated, cycling directly from the main tank. I’ve set a thin piece of filter sponge inside the exit stream at the surface to keep babies from escaping – the current isn’t strong enough for them to get trapped (1″ opening x 1/8″ water depth). I especially like that it doesn’t require a bunch more maintenance or take any space away within the existing tank. It’s versatile, and can be used whenever fish/lotls need to be isolated or acclimated.

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  3. L. Maneeley

    Fits the small side of my 10g mixed reef tank perfectly, holds macroalgae an pods, with just enough flow coming through the valve to allow a small stream of water through the “return” into my tank

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  4. L. Maneeley

    Years ago, I had a fish give birth only to have the fry get IMMEDIATELEY eaten by its mother. I was so sad and disappointed. I new I had to get a “Breeder Box”. I got a super cheap one that just sits inside the tank. I mainly used it to let the fry mature a little bit before getting moved back into the main tank, or help heal a fish that was getting bullied recover its strength before rejoining his friends. After many months of tryin to find out why some fish that I put in there died immediately. I came to the conclusion that the water flow in this box was so so poor that all of the waste was being stored in the box and there was not adequate oxygen getting into the box through the small slits on the sides.

    Then I found the Fluval Multi-Chamber holding and breeding box and holy cow, what a difference. It incredibly easy and intuitive to set up, and is absolutely the perfect size for almost any application. Even on relatively small tank like a 10 gal. Currently, I have a Molly with a fin injury in one compartment, and the other 2/3rds of the tank are housing her baby fry. The room that I keep one of my tanks in, which currently has the Fluval box on in, gets very cold at night, 60-61 degrees. I was worried that since it hangs off the front and is just plastic that the temp in the box would lower drastically. I am happy to report that the temperature did not budge from the main tank temp with no additional heaters or anything, i have a 50w and a 25 w heater in the tank, but I’m confident that you could be perfectly fine with just one 25 or 50W depending on the ambient temperature of the room. The only thing i would be mindful of, is trying to keep super small fry (I’m talking 1-2 days old) in the left portion of the tank. I had a single fry get pressed up against the grate the flows back into the tank. I don’t know if he was sick or weak, or if the current got him, but in thousands of fry run through this box, I’ve only had a single loss. so my best practice, if you don’t need the whole box, is to partition off the far right slot, put your fish in the left and put the drain with the bigger slats in the outflow spot on the right. That allows more water to flow through the box and greatly decreases build up of debris (if you’re like me and have a heavy hand when it comes to feeding fry.

    The only problem with this box is that I don’t have one for all of my tanks!

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  5. h0MbrE

    I bought one of these for my angelfish breeding. I have some pairs that throw a percentage of albino fry and could never manage to get any of the albinos to survive until I tried one of these breeding boxes. Now, I am getting unbelievably high survival rates with my albino fry! I now have three of these and a fourth one is on it’s way! And they are very affordable.

    I can’t say enough good about these boxes. They really simplify raising fry. They are VERY easy to clean and maintain. They can be used not only as breeding/fry boxes, but also as slow-drip acclamation devices, isolation tanks for stressed or “bullied” fish, and great holding tanks for taking pictures of your fish, and the added benefit of having the stability of the larger tank that the box is hanging on is priceless. To do a water change for your fry, simply do a water change in the main tank, and you never even have to move the fish in the box or worry about them during water changes.

    As I mentioned already the price is fair, not too expensive at all. The instructions were simple and the design is brilliant.

    The only cons I guess I can think of are that you can’t use a top for the tank they are hanging on unless you devise a custom top that can fit around the part that hangs over the front of the tank. The other thing is that they come with tow “grates” that cover the overflow, one with small gaps for smaller fry, and one with larger gaps for once the fry are grown out a little. The problem with the grate covers with angelfish is that even with the smaller gapped grate, fry can squeeze through and get washed back into the main tank. To remedy this I bought some foam sponge from hobby lobby and cut small squares to replace the grate for the first week or so until the fry are too big to fit through the gaps. You will want to cut the foam sponge pieces to fit snugly but not tightly enough to restrict too much water flow otherwise you can overflow the box and wash some fry back into the tank that way. With a little adjusting of the trickle and just the right size sponge block, you can keep the fry in the box no problem. As great as these are I can’t justify taking away a star for that little issue. If it weren’t for these breeder boxes I wouldn’t be able to raise the albinos… at least not without quitting my job and tending to them full time!

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    Fluval Multi-Chamber Holding and Breeding Box, Large – Up To 3 Separate Housing Compartments
    Fluval Multi-Chamber Holding and Breeding Box, Large – Up To 3 Separate Housing Compartments


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