Both the Fluval Spec III and Spec V Aquariums make great homes for Betta fish, otherwise known as Siamese Fighting Fish. Many people make the mistake of keeping their Betta fish in very small, 1 gallon containers sold at the fish store. If you are at this page, you probably realize that this is a mistake and want your wonderful Betta to have a better home with more water.

The Fluval Spec aquariums are a great choice to house a Betta, either the three gallon Spec III, or even better – the 5 gallon Spec V. Having 3 or 5 gallons will make the water parameters much better for your fish. Betta fish are a breed of fish with some specific needs; I will tell you how to make your Fluval Spec aquarium Betta friendly.

Betta’s are no different than any other tropical fish: they need good water parameters to survive and thrive. They like high quality foods. Water parameters will stay better longer if you keep a few live plants in the aquarium. Keeping Betta’s is simple, but they have a few special needs. Betta’s are known for their ornate and flowing fins. This means that they like an aquarium with slower and gentler water so that they are not constantly buffeted by the high flow. Since they are a tropical fish, they prefer water temperatures in the upper 70’s, preferably keeping the temperature in the range of 78°F to 80°F (25.5°C to 26.7°C). Let’s look at how to make these conditions work in a Spec aquarium.

Water Quantity: Reducing the Flow in your Fluval Spec

The Fluval Spec aquariums have a great leg up on the standard 1 gallon bowl that many people keep Betta fish in because of the great internal filtration pump. This will put you way ahead of the curve for maintaining good water conditions. However, this internal filtration pump also leads to the main shortfall for keeping a Betta in that the water flow is simply too great. Without some modifications the resulting currents will be too high and will buffet the Betta’s large fins and wear him or her out over time. This causes stress, which can lead to sicknesses/disease and may shorten their life. The good news is there are several easy ways to reduce the flow rate in the Spec aquarium and make it more Betta friendly.

The first is the simplest. The stock pump has an adjustment on it to vary the flow rate. It actually does not change the pump speed but simply serves to impart a flow restriction at the water intake to the pump. This restriction will lower the flow throughout the aquarium and make life easier on the Betta.

The adjustment is found on the side of the pump; there are labels with a ‘plus’ and a ‘minus’. Simply slide the baffle to the ‘minus’ side and that’s it. For keeping a Betta, I would go ahead and move this all the way to the lowest flow.

The second modification is a bit more involved, but very effective to reduce the flow rate in the main display. The outlet from the pump travels up through the flow tube, through a 90° bend, and out the return nozzle into the tank. One way to reduce the water flowing out of the return nozzle and into the tank is to put several small holes in the flow tube. This divides the water from the pump; most will travel as intended but some will be diverted out the holes in the flow tube. It will then circulate through the pump section of the aquarium and go back down to the pump inlet. I go into detail for how to do this in my Flow Tube Modification page, as well as detailing why this flow change will be beneficial, especially if you choose to place a heater in the open area of the pump section.

With these two simple mods to your aquarium, you have reduced the flow rate considerably to make your tank more Betta friendly while still maintaining plenty of flow for good filtration. Next up is how to make the water flow more hospitable to your long finned friend.

Water Quality: Diffusing the Flow in Your Fluval Spec

Even with reducing the flow rate considerably, the water still exits the stock return nozzle in a very harsh jet. Your Betta will have places that it can shelter from the high velocity water, but much of the aquarium in a straight line back from the nozzle will push him / her around. You need to somehow diffuse the water from the return nozzle so that it isn’t coming out in a straight line but is spread out evenly and slowly.

There are various methods to this, but they all revolve around utilizing a sponge of some sort. I haven’t tried this, but some internet forms have claimed good results from taking a pea size piece of aquarium foam (you can actually use a corner of material from the stock filter in the Spec) and placing it inside the flow nozzle. Start with a piece about the size of a bean, cut from the edge of your filter sponge. Turn the pump off, remove the return nozzle from inside the display tank, wedge the piece of foam inside the nozzle and replace it. Turn the pump on to test. If the flow is too restricted, just take it out, cut a tiny bit more off, and try again. This method is nice because it costs nothing and doesn’t change the appearance of your equipment. The downside is that this piece of sponge might not stay put and it will need to be cleaned / replaced occasionally as it wears out.

An alternative to this is to place a piece of foam outside the nozzle to cover it and diffuse the flow. Fluval makes a replacement filter for their Edge series of aquariums that fits perfectly. Search for the Fluval Edge Pre-Filter Sponge . It is a cylindrical sponge that fits over the return nozzle and will very effectively make for diffused and slow water flow for your Betta.

I have tried this modification out myself and have a page on it here.

Outflow: Taming Those Fin Nipping Slots

The last flow modifications are relating to the outflow from the tank back to the filter section. At the top of the baffle between the display tank and the filter section are a series of vertical slots that allow flow into the filter section. The flow speed is generally slow through these slots; however, some Bettas have been known to sleep up against these grates and their fins can get caught and torn in them.

If this is the case for your Betta, you can cover the slots to keep their fins from entering. Sponge material can work here as well. Simply cut a rectangular section with a slot in the center most of the way through. wedge the sponge down over the black baffle with the slots between the two sections of sponge. You can also use zip ties to simply affix a flat sheet of sponge onto the outer face of the slots.

Another optiion is to get some plastic mesh canvas that people use for cross sticking. You can find it at craft stores and it comes in white or black. Black blends in better with the baffle. Just take a small piece cut to size to cover the slots and use zip ties to affix into place.

An even cleaner option that I have discovered is to make an overflow cover out of stainless steel – I have a page showing how to make your own.

The last thing to mention is that there is a bypass slot toward the bottom of the black plastic baffle between the display tank and the filter section. Your Betta’s fins can get caught in this slot and there are other reasons for plugging this bypass that i detail on this page. It’s best to tackle this before you get water in the aquarium by filling with aquarium safe silicone. However, a bit of sponge can be wedged in there if you already have your tank up and running.

Maintaining Water Temperature for your Betta

Depending on how warm you can keep your home, you may not need a heater at all for your Betta. However, maintaining a stress-free fish hinges on keeping the water temperature as consistent as possible. If your house temperature drops down to the point that maintaining aquarium temperatures of at least 75°F (23.9°C) is not possible, then you should consider getting a heater.

There are several options for placing a heater in the Fluval Spec Aquariums; look for a power of around 25 watts. I have a Hydor Theo 50 watt wedged in the pump section of our Spec V. It is a great little heater and fits perfectly in this hidden location. The temperature settings on heaters are often not calibrated perfectly – make sure to verify the heater operation and set point with a separate thermometer.

If you really want to ensure consistent and safe temperatures for your Betta, consider utilizing a temperature controller to ensure the heater never fails in the ‘on’ position and kills your beloved pet.

Some people with hotter homes will have the opposite problem and will have a hard time maintaing temperatures of no more than 80°F (26.7°C). Consider adding a fan if you are in this situation. Evaporative cooling can be very effective to lower your tank temperature in the summer.

Please don’t think you need to take all the measures I am suggesting to make your tank Betta friendly, but I hope these very simple ideas will help you come up with creative ideas to modify your Fluval Spec to be the perfect home to your pet.

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