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"Betta Proofing" Your Fluval Spec V And Similar Filters

Hi! In this article, I will be covering how to modify the filter and it's parts on the Fluval Spec V (or similar build-in filters). This article is mainly focused on making this tank more suitable for bettas or small fish that could get sucked into the overflow or don't like being blown around.


Why modify the overflow?
I have found that the source of my betta's terrible fin rot was not poor water quality or sharp decorations, but actually the overflow on this tank. You see, the pump in the filter compartment is strong enough that there is a fairly stong current. If you betta is like mine and chooses to sleep on the overflow, their fins get sucked in and torn to shreds. This may sound bad, but there is a simple fix for this that will keep your fish safe.

Modifing the overflow:
  1. Unplug all cables, cords, etc.
  2. Cut some filter floss so that it is long enough to over the whole grill part of the overflow and has a bit to go over the back
  3. Take a zip tie and wrap it around the filter floss and through the overflow and zip it tight
  4. Trim the excess and make sure that the end part is not in the tank

Why modify the output?
In months that I have used this tank, I have noticed that the output is very stong. With most fish, this isn't a problem, but with bettas with long fins, it is. Acorn has been blown around the tank and it is very sad to watch. Forturatly, I have thought of a solution.

Modifing the output:
  1. Unplug all cables, cords, etc.
  2. Cut the coarse sponge into a 1" by 0.5" rectangle
  3. Remove the nozzle of the output
  4. Roll the sponge up and jam the rectangle into the tube with either your fingers or tweezers
  5. Put the nozzle back on
  6. Plug the filter back in and make sure the you blockade is working
Possible problems (and solutions):
Lack of surface agitation/stagnant water
S: Cut the sponge so that is it still 1" by 0.5", but is less tall

P: Betta is working his way under the filter floss and onto the overflow
S: Add more zip ties so that there is no space he/she can slip under

P: Filter floss is gross and slimy
S: This is likely to happen every few months, so when it does, replace it

P: Flow rate started off fine, but is getting worse
S: Check and make sure that the sponge you put in the output is nice and clean as this is most likely the source of the problem

Hope this helps and good luck!
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Thanks for the filter floss tip! This is a cheap & simple way to cover the dangerous overflow grill on the Spec V. Everyone putting a betta in these tanks needs to do this, I had a plakat get torn so badly from the suction of the grill that it ripped his body open and killed him :( The sponge over the nozzle is also very necessary otherwise your betta will just get tossed around the tank all the time.
No problem! Glad I could help!
Very helpful! Especially good knowledge considering how many of these portrait tanks are perfect for bettas in size but not with the technology they’re equipped with.
Thank you so much!
Great info thank you!
No problem!
Really helpful advice, especially for such a common tank that new fishkeepers and betta-owners buy.
Thank you so much!
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