Tetra Whisper 20i With Betta? Help.


New Member
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Just started
So I have a ten gallon tank I'm going to be setting up, and my father went out and asked some girl at a reptile store what filter to use in it... Obviously this girl wasn't very knowledgeable because she told him "bettas don't need filters.... but the tetra whisper 20i is good!" WHAT? For a 10g tank????? (Dad said she said you can't "over filter" the water... ok but what about the fish's livelyhood and desire to explore/move around??!) I hate this filter, looking at the intake alone makes me nervous, but my dad is not the kind of man who takes things back, and will be really angry if I say something about how useless the filter is, since it'll come off as ungrateful. (Which I'm not, just frustrated that he took over MY aquarium with what HE wants....)

So, what do I do? I've seen a thread where people recommend aquarium floss, of which I have none and probably wont be able to buy anytime soon. It seems pretty expensive, is there a cheaper alternative? (I'm thinking the material of an old t shirt but that probably only shows how stupid I am --- I just need to think quick as its his birthday and he wants me to set it up today). I've also seen people recommend covering the intake with a sponge.... Is this on the outside of the filter or the inside? And if the inside, does it not keep the water from being filtered? Also, can I use any sponge from like a grocery store or something (as long as it doesn't come pre-packaged with soap)? Or does it have to be for an aquarium specifically?

I've heard about the bottle trick also, which I will try, but the whisper has more of a lip at the top, so I'm not sure how it'll stay on there, even with tape. I'm really just so overwhelmed. I'm attached to my fish (he's my first one and I've had him for eight months) so I don't want to cause harm or hurt him with this massive disgusting thing! Honestly, if I was him... I'd be terrified.

Also, since I'm starting the cycle of the aquarium with the filter and the fish, what does that mean as far as water changes go? (I have a heater -- just want to put that out there so everyone who may wonder can rest easy.)

Thanks in advanced for your help! Please try to be as detailed as possible with any answers, as I want to make certain I'm doing everything right. I really appreciate this community, as I am a complete novice.


Fishlore VIP
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3 years
I used that filter in a five gallon before, it was not good.
Personally, I do not recommend that one with bettas. I recommend sponge filters or the Aqueon Internal E series filters.
Return the filter and get a new one.

For the cycle, you are doing it with the betta? I would be wary about the betta not surviving if ammonia gets too high.
I would do a water change if ammonia goes beyond 1PPM, for sure.
You are doing just fine so far!


Well Known Member
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5 to 10 years
I think the tetra whisper internal filters are great. Not sure why you are so worried. If it's flow it basically has none as long as the water level is around the same height. I think the 20i is too big though, that's for a 20 gallon I think. I only use the smaller ones because I feel that the ones for 20 gallons and above aren't gonna cut it.
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