Choosing Between the Fluval Spec III and V Aquariums

For those interested in a freshwater aquarium from the Fluval Spec lineup, you first have to decide between the two models, the Spec III and the Spec V.  I’ll run through the similarities and differences between the two that will hopefully help in deciding between them.

How are the Spec III and Spec V the Same:

First of all, I have reviews of both the Spec III and the Spec V where I go into detail for both of these aquariums. They are the same concept, which is an all-in-one tank that includes light and filtration system all in one contained unit.

Fluval Spec III and Spec V Aquariums - Front View

The filtration systems work the same and share the same pump and piping fittings.   The filter media (sponge, bio-max, and activated carbon) are exactly the same between these models.

The light concept is the same, with a longer fixture for the Spec V (to match the footprint).

Spec III vs. Spec V – Tale of the Tape:

It’s easy to see where the Spec III and Spec V differ and that is in size.  The designation “III” and “V” refers to the approximate volume (in gallons) of each aquarium.

Fluval Spec III and Spec V Aquariums - footprint comparison

Beyond just volume, the two differ in size and shape. The III is more cube-like with width and length close to depth.  The III is actually taller than the V.

The Spec V is more panoramic in size with a much longer display area.

The Spec V has dimensions as follows:

  • Overall Footprint: Length = 20-1/2″ (521 mm); Width = 7-1/2″ (191 mm). The footprint measures the black plastic frame at the bottom; the actual glass dimensions are less than this.
  • Overall Height: 11-3/4″ (298 mm). This is measured from the surface that the aquarium rest on to the top edge of the glass.
  • Overall Height Including Light: 12-3/4″ (324 mm)
  • Main Display Section: Length = 17-1/8″ (435 mm); Width = 6-3/8″ (162 mm)
  • Pump Section: Length = 2-1/16″ (52 mm); Width = 2″ (51 mm)
  • Filter Section: Length = 2-1/16″ (52 mm); Width = 4-5/8″ (117 mm)
  • Filter Section Height: 9-1/8″ (232 mm). This is from the top of the baffle that the filter media rests on to the top edge of the glass
    Inside Height: 10-9/16″ (268 mm). This is for all compartments, measured from the top of bottom glass to the top edge of the glass.

The Spec III has dimensions as follows:

  • Overall Footprint: Length = 10-7/8″ (276 mm); Width = 9″ (229 mm). The footprint measures the plastic frame at the bottom; the actual glass dimensions are less than this.
  • Overall Height: 11-9/16″ (294 mm). This is measured from the surface that the aquarium rest on to the top edge of the glass. The acrylic top adds 2 mm
  • Overall Height Including Light: 13″ (330 mm)
  • Main Display Section (inside dimensions): Length = 7-3/4″ (197 mm); Width = 7-15/16″ (202 mm)
  • Pump and Filter Section Length = 2-1/8″ (54 mm)
  • Pump Section Width = 3-9/16″ (90 mm)
  • Filter Section Width = 4-5/16″ (110 mm)
  • Filter Section Height: 9-5/16″ (237 mm). This is from the top of the baffle that the filter media rests on to the top edge of the glass
  • Inside Height: 10-3/8″ (264 mm). This is for all compartments, measured from the top of bottom glass to the top edge of the glass.

Which Spec is Best for You:

I think the deciding factors for which Spec is best falls under the following: critters (what fish/shrimp/inverts you want to keep), shape (preference for aquascaping), size (overall footprint and height).

Fluval Spec III and Spec V Aquariums - lights

First let’s discuss the occupants.  I have written about how to select what animals to keep in both the Spec V and the Spec III.  Bottom line is that for both options, you probably can’t keep as many fish as you would think, or want, and maintain health and longevity for the fish.

The Spec V has an advantage in what you can keep as it has enough volume to keep small schools of fish and some inverts.  The Spec III is generally too small to recommend keeping a group of fish. If you are looking to keep a single fish, like a Betta, the Spec III will work great.

Next is shape.  The two aquariums differ greatly in aspect ratio as I have mentioned.  The V is longer for more horizontal layouts.  The III is more cube like.  Some may prefer creating aquascapes for the cube shape and will gravitate to the III.  Some, like myself, have a much easier time creating rock and wood layouts in a longer tank like the V.

Fluval Spec III and Spec V Aquariums - top view

Finally, there is overall size.  If space is limited, many people may only have room for the smaller footprint of the Spec III.  For us, we had the end of a narrow countertop to place our Spec; the V fit nicely on this long and narrow shape.

Final Thoughts on Choosing Between the Spec V and III:

Most people will be able to decide easily between the two based on what they want and where the tank will go.  I will advise again that if you are looking to keep more than a single fish, you should strongly consider moving to the larger V over the III.  The extra few gallons of water helps greatly in crossing the threshold of size that is suitable for a group of fish.

 

2 thoughts on “Choosing Between the Fluval Spec III and V Aquariums

  1. Great article. I am setting up a new Spec . . . I keep playing with the idea of ditching the internal workings and going with an Azoo palm filter . . . have you had any experience with alternative filters in the specs?

    Thanks.

    • Have you tried out the tank yet? I have used ours for over 3 years and I think the stock filtration is pretty darn good. Adding a HOB would kind-of defeat the purpose of an all-in-one (just my opinion).

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