# Fluval Spec V vs Flex



## Smooshface (May 26, 2016)

Hello all, I'm getting ready to get my son his first fish tank, we are debating between the Spec V and the Flex (9g).

We plan to have plants, and a few nano fish like Furcata Rainbows or CPD's as well as some cherry shrimp, or he might get a betta, he's having trouble deciding. (Luckily, we've got time since we will cycle it first)

Which of the two tanks do you guys recommend for shrimp/fish/plants. We would prefer to use the stock light/filter and of course add a heater. There won't be CO2, but I do use Thrive for my plants in my tanks and am not opposed to using it in his tank as well.


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## Fishbuds (May 14, 2017)

After running a fluval flex 9 for 6 months I can say from my experiance that it was cursed. The first one I received was broken in the box. The glass is very thin on them. About three months in, only the white portion of the leds worked and now it got covered with bga in a matter of days (not really the tanks fault I guess). If your going to go betta the flow on the filter pump is too strong and will have to be modified in some manner. Too bad though because I still think it looks pretty cool with the curved glass and I'm sure other people have had much better luck with it. I haven't had the opportunity to run a Spec V yet but these are some of the issues I've had with the flex.


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## Thelongsnail (Dec 2, 2015)

I've been using my fluval flex (15g) for over a year, and have mixed reviews to be honest

CONS:
a) the slats in the integrated filter box are large enough for small fish to get in and out

b) fish can easily jump into the back of the tank and even on top of the filter media

c) as said previously, the filter is too strong for long-finned bettas

d) the filter can be difficult to take apart, although you shouln't really have to (unless a fish gets in)

Most of these are easily modded, but it's annoying to have to do. 

PROS
a) the heater is easily hidden in the back compartment

b) the stock light grows low light plants pretty well

c) some people really like the look of the bow front

d) it has a remote control light with different colour options, although the lightning simulation seems a bit cruel

If I had to choose between the two though, I'd go with the fluval flex, simply because it's got an extra 4 gallons to stock as you please.

Photos attached below so you can see lighting levels/how I've modded the filter, excuse the crappy set up and photography


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## Smooshface (May 26, 2016)

Thelongsnail said:


> I've been using my fluval flex (15g) for over a year, and have mixed reviews to be honest
> 
> CONS:
> a) the slats in the integrated filter box are large enough for small fish to get in and out
> ...


This looks really nice though. Can you just put a piece of foam or mesh behind the grates in the back to keep fish from swimming in them? And are they too strong for non-betta fish if he decides to go with the nano fish instead? At our local pet-store, there is literally a 5 dollar difference, so just trying to decide which way to go.


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## kaldurak (May 2, 2010)

More volume equates to easier stability of the water, so as a previous spec v owner I would say grab the larger tank. Both tanks are exceedingly versatile with "mods" to make them more friendly to fish like bettas who do better with a lower flow. Two things I did was place a prefilter sponge over the outflow of the Spec V and stuffed large pore sponge in the intake portion. This diffused the flow and also stopped betta fins and shrimplets from being sucked into the intake area.


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## Thelongsnail (Dec 2, 2015)

Thanks! It still needs some planting done but it's alright so far  

You could try foam, I did but unfortunately a small cory got stuck and died. I know it's worked for others though. They sell clip-on covers (I even think some of the newer gens come with them) that would stop most fish from getting in - not sure I'd recommend it with fry or juvenile nano fish, but they would do the job with adults.

I think it depends on the nano fish when it comes to filter strength, but forktail rainbows would probably love it as they like higher flow. Even if it is too strong, it's easily sorted with some bits of filter sponge and mesh bag.

Overall, if there's only $5 difference between the two, I'd definitely go with the flex because it has so much more space. They're good looking and easy to use little tanks, just have a few issues that really should have been sorted before starting production.


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## Proteus01 (Mar 12, 2017)

The Spec V is a very nice total package, with an effective light for growing most of the plants folks want. The size is just fine for a betta and some snails (maybe just one nerite). 
The Flex is bigger, and has the bow front (which I don’t really like). More fish are possible. The light seems less effective, but just fine for low light plants. 

Where are you going to put the tank? Would you view it mostly straight-on, or low, or at an angle? The Flex is deeper, letting you make some nice ‘scapes that need a larger footprint. The Spec has that short-depth tall and wide look, or a peninsula setup for ‘scapes. The lids and back are quite different, which could also be a plus or minus based on your scape and viewing direction.


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## Smooshface (May 26, 2016)

Proteus01 said:


> The Spec V is a very nice total package, with an effective light for growing most of the plants folks want. The size is just fine for a betta and some snails (maybe just one nerite).
> The Flex is bigger, and has the bow front (which I don’t really like). More fish are possible. The light seems less effective, but just fine for low light plants.
> 
> Where are you going to put the tank? Would you view it mostly straight-on, or low, or at an angle? The Flex is deeper, letting you make some nice ‘scapes that need a larger footprint. The Spec has that short-depth tall and wide look, or a peninsula setup for ‘scapes. The lids and back are quite different, which could also be a plus or minus based on your scape and viewing direction.


Well, my son is 5, and he'll be helping me maintain the tank, but it will be in his room, so at his age, pretty much everything is up or straight on, he definitely won't be looking down into it, so I think we are safe there.

I personally prefer the longish tanks, but I thought at 9 gallons, we could do a bit more with it and get a few more fish if he decides to not go the betta route.

However, I didn't know if the Flex did a good job with plants.


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## SueD (Nov 20, 2010)

I have 2 of the Spec V's and love them. I've grown anubias, java fern and a hygro compacta with the original light on one (and mine is the older version light). The other I changed the light to a Finnex (older version of FugeRay) and grow crypts, anubias and moss in here. In both of these tanks I added a sponge from the Aqua Clear 50 filters above the Spec V sponge and it has kept fish out. I have occasionally found shrimp back there.

I have no experience with the Flex, but there is now a Spec 16 if you want a bit more room, although it is a bit pricier. I'm waiting to see if I can find a nice sale sometime. I got both of my Spec V's that way for about $59. I don't think you can go wrong with this tank.


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## Smooshface (May 26, 2016)

SueD said:


> I have 2 of the Spec V's and love them. I've grown anubias, java fern and a hygro compacta with the original light on one (and mine is the older version light). The other I changed the light to a Finnex (older version of FugeRay) and grow crypts, anubias and moss in here. In both of these tanks I added a sponge from the Aqua Clear 50 filters above the Spec V sponge and it has kept fish out. I have occasionally found shrimp back there.
> 
> I have no experience with the Flex, but there is now a Spec 16 if you want a bit more room, although it is a bit pricier. I'm waiting to see if I can find a nice sale sometime. I got both of my Spec V's that way for about $59. I don't think you can go wrong with this tank.


If I found it for 59, it would be a no-brainer. Our LFS has the Spec V for 99 and the Flex for 104. At those prices, it's hard to pass up another 4 gallons. It appears the filteration method is about the same, so it's mostly, is the light okay on the flex. I do like the shape of the Spec more, but to almost double in size, that's better for the fish and I can get more in there.

But like I said, I find a good sale, it's going to be whichever I see super cheap if they are both good.


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## SueD (Nov 20, 2010)

Kens Fish has it for $72.95 at the moment with free shipping over $49.

Fluval Spec V Aquarium 5 Gallon


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## Smooshface (May 26, 2016)

That's a pretty good price. If I were ready to buy now I'd quite possibly grab that.


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## SueD (Nov 20, 2010)

Not sure how eager or patient you are for the tank, but may see more sales around the upcoming holidays. I think I got my 2nd one on Black Friday from Petsmart. Wasn't looking for another one, but couldn't resist the price.


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## Smooshface (May 26, 2016)

Yeah, I won't be buying anything till we rearrange his room, so we have time, Black Friday does seem like it would be a good time to look.


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