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

This breeder box has been perfect for raising my celestial pearl danio fry. It was easy to assemble, and I really appreciate how simple it is to access the inside for both feeding and cleaning. I did make a small modification by adding a sponge to the return since the provided grates were a bit too large and could allow fry to slip through. With that adjustment, it works wonderfully. Overall, I highly recommend this breeder box for anyone raising fry.

So I've bred peacock gudgeons and hatched most of the eggs within this container. It was attached to its own little 5 gallon tank with a HOB with carbon and extra sponge for proper filtration, keeping nitrate and nitrite at 0 despite the several-times-a-day feedings. The box definitely has potential to turn your fry container into a fry washing machine, little guys get tumbled around from the flow. The little adjuster on the airline itself did nothing for me, so I had mine hooked up to the system of my rack that let me change airflow directly from the pump. Had to lower that a decent chunk, otherwise the water flow was simply too strong. Even with that, I put some aquarium sponge on a little skewer and placed it right under the water output to catch most of the impact. I also added a piece of sponge on the outflow, because the little grate it comes with is just too big. My little fry kept escaping. I eventually learned that my fry are even small enough to go into and through the damn sponge I put in there, so I had to use something finer (which clogged easier). I also added some floaters and java moss to help with both filtration and hiding space for my little buggers. Unless you have fry that's too big to go through the little grate you definitely will need modifications. But besides all that, it's a fantastic option for hatching eggs and raising fry. My little guys are by now big enough to swim in the 5g freely while growing a little more without risk of ending up in the HOB. Given how well this entire setup worked for me I'll be getting more in the future. I've yet to try it for egg scatterers along with the one item from I believe penplax for automatic egg-harvesting, but I'll get there. And for that I'll need another one! I definitely can recommend it. It kept all my fry in a small space meaning I could give them more accurate feedings, and hook it up to its own tank to have a big water volume for great parameters. Amazing!

I've been using the 0.5 gallon breeder box for a few months now and it has worked really well so far. I use it for drip acclimation, as a holding tank for new fish/shrimp, and as a breeding tank to raise fry. It is very convenient, efficient, and easy to set up. Many of the negative reviews mention the little gate piece allowing fry to escape into the main tank. This is easily remedied by adding a piece of sponge filter in front of the gate. It is a little bit on the noisy side, but I actually enjoy the sounds of bubbles and trickling water. Other than that, the only two issues I have is that the the male connection to the airline tubing can get clogged with bacteria/biofilm which reduces the flow. This can be fixed by simply cleaning it with a test tube brush. Flow is also reduced if the water level in the main tank is lower, so just keep that in mind. The other issue is that waste can accumilate on the bottom of the chamber and it is not efficiently removed. I say this because all of my cory catfish fry died presumably because of the excess bacteria buildup on the bottom of the chamber. However, I probably overfed with first bites and didn't do a good job of siphoning out the waste. Despite these potential drawbacks, I believe that this breeder box is the best on the market.

I love this little box for my pregnant shrimp! It easily fits onto my 75 gallon aquarium. I currently have 5 pregnant shrimp in here. They seem to have plenty of room, for now. I’m not how this will work or if I’ll be able to save babies. I’m certainly going to try. The box was super easy to set up. It only took a few minutes. I was worried because the directions said the aquarium water level had to be within 2” of the top. Mine is not. I have it lower than that. Thankfully, it works just fine. I get a steady stream of water pumping in and flowing out. I think this little box is genius! I’ll probably use it to house some plants or maybe other fish babies, in the future. Also, I wrapped a little quilt batting around the output to prevent anything from getting dumped back into the aquarium.

The Fluval Multi-Chamber Holding and Breeding Box (Medium) is an incredibly well-designed accessory for anyone who keeps fish, breeds them, or needs a safe space for fry or injured tank mates. The multiple compartments offer great flexibility — you can separate fry by size, isolate a stressed fish, or use it as a temporary acclimation area. One of the best features is the continuous water flow from the main aquarium, which keeps the environment stable and oxygen-rich without stressing the inhabitants. Setup is very simple, and the box attaches securely to the tank with no wobbling. The clear plastic allows easy monitoring, and the layout makes feeding and maintenance effortless. Overall, this breeding box is sturdy, thoughtfully designed, and extremely versatile. A must-have for breeders, hobbyists raising fry, or anyone who needs a reliable isolation space. Highly recommended! 🐟✨

I like these, I’ve bought 3 over the past 2 months. However this first one I bought, when trying to get the airline tube off it fully pulled, broke off, the part it was attached to. So now I can’t use that entire water flow mechanism for it. Really frustrating and worried it’s going to happen to the other two I bought after this

So as you see in my video I have experience with the small, and now I own the large version of this breeder box. It works great. Some reviews say people had issues. As you see, it doesn't leak and the pegs didn't break off like some others said. The pegs add and remove leverage so that it can sit correctly. You want it to be aligned perpendicular with the rim of your tank or if anything SLIGHTLY angled downward INTO the tank. You do not want the bottom of the breeder box to be pushed out from the tank. I could see that as a reason why the pegs would break for some people. You don't want the bottom too far in. I could see that causing the box to leak from the front but I dont see how that could ruin your marriage. I have my pegs on number 4 but the glass and rim is thick on my 75 gallon. Front of the breeder box should be more or less parallel with the tank. Don't put your flow too high. I have a constant drip. Maybe 1 to 4 drops per second but it needs to be dripping into the box constantly. It gives a small stream from the slit and a constant drip into the aquarium. It doesn't make lots of noise. I haven't had issues with this method in 2 years. This combined with my egg incubator is invaluable when it comes to preserving numbers. The small version does not have a lock. I don't use the lock on the big one. I dont like the design of it. I didn't need instructions because I'm not incompetent but some people may need them.

It came with no instructions, but it was pretty easy to figure out. The only thing I had trouble with trying to figure out is those two tabs that go underneath where it hooks onto the tank as seen in the photo I took in between the tank and the box underneath. Still don't fully understand the purpose of those two tabs. But it's whatever it may be. Right now it's on the back of a 29 gallon. It's a great box to breed fish in, put their eggs in, act as a holding tank, or even use as a specimen container if ur looking to sell fish or examine them! And if ur wondering what those two little rubber things are, they're the clips to hold the top down if u have any aquatic friends that like to jump or escape. I see a lot of people say they have gargling or sputtering issues with the set, but mine came with a cap the has another hole on the side and I just put it on there end of the intake tube on the inside and it's as silent as can be. At least for my ears. So if urs came with a clear cap that has a hole on the side of it, stick it in there and see what it does for urs. So for the lack of instructions for everything that come with it, i give it 4 out of 5. Otherwise if it had instructions to come with it, i give it 5 out of 5! Great box!!! Definitely recommend! Oh! The air pump I have that's running it is a 3W 2 outlet adjustable air pump for the stone and the intake. Works really good! Good flow! The 2 air flow control valves, the 2 check valves, and the stone with the suction cup all came with the air pump I ordered separately with this. The purple artificial plants I ordered separately as well. I figured it'd be good to put those in to help them feel safer and hopefully be able to see them better as they move around. Also provide more surface for bio film and beneficial bacteria to grow on. I would've put real plants in but hornwort tends to grow pretty fast and it's hard to see those little white babies swim around in them. Hah So I put a small dwarf water lettuce in there instead to see how it goes. But anyways, hopefully this review will help those who are thinking about getting one of these. In my personal opinion, don't hesitate to get this because it's so versatile and u can use it for so many things other than just breeding. It's a great thing to have in ur arsenal as a fish keeper/breeder and I think everybody should have them especially if they're just starting out in the hobby. Have a nice day!!