# Will A Female Betta Kill Tetras??



## DukeD1989 (Jan 10, 2017)

So I seem to be losing neon tetra out of the blue and it is pretty darn worrisome.
I have a 10-gallon tank. For the past two months it has had one female betta, HAD 8 tetra, and some live plants. I did a full nitrogen cycle before adding any fish - and according to my API master kit the water levels (for nitrates, ammonia, etc) are all where they should be. Temp. is usually around 79 degrees. 

About two weeks ago I found a dead tetra. It was rather shocking. I went to bed with 8 and woke up with 7. There was no sign of any illness - no discoloration, no sluggishness, etc. I just figured that maybe it wasn't long for this world. Then a week later another was dead and one was missing. Again this happened overnight without any prior signs that anything was wrong. Yet there were 7 when I went to bed but when I woke up that morning there were only 5 alive and one body...and one just missing completely (huh?!?). I've checked and rechecked the water levels. They are fine. The filter has a sponge over the intake so it wasn't sucked up or anything. 

So, what could it be? I worry my betta may have killed them She isn't very aggressive though. There have been occasions when she would swim rapidly towards one - but never actually attack. Will a female betta kill like this? Or maybe it is something to do with water hardness? Can that kill overnight like this? The whole situation is weird. They were fine for months. Nothing has changed since. Water levels have been the same. Hardness, temp., etc has all been the same. Yet now I'm down 3 in a two-week span.

If anyone has dealt with a similar situation - or might have any answers it would be greatly appreciated!

Tank parameters:
Hardness (per API strip): 150 Hard Ammonia (master kit): 0ppm Nitrite (master kit): 0ppm Nitrate (master kit): 20ppm pH (master kit): 7.2


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## bluebutterfly123 (Feb 23, 2017)

I know I was told not to put tetras with a betta.. But my worry would be to where one of the fish disappeared to... You should find it.. I'm sure the betta didn't eat it bone and all... It's decaying body will cause a spike.. Maybe a pic of the tank can help us figure out what's going on... But 
I once did a diy background for my 10 gallon tank.. My betta found a way to stick itself into a gap between the glass I didn't even see.. Spent a day looking for the poor little guy... Ripped the whole tank apart.. And finally found him.. 😢


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## ThatFishThough (Jan 15, 2016)

Possible. Take her out and put her into QT and see if any more die.

-- 8 Neons in a 10 is a bit crowded. I wouldn't recommend them for anything under a 20 Long.


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## RussellTheShihTzu (Mar 19, 2013)

Neon Tetra are very sensitive fish and especially to water hardness as they are soft-water fish. That could be your problem; it also takes time for water hardness to kill. Were there any symptoms at all? Are all of the Neons nice and fat? Are they eating enough? There is also something called "Neon Tetra Disease." I've linked some information below.

I doubt your female is killing them; few fish/shrimp succumb to Betta predation unless they are already weak.

BTW, 10-12 shoaling Nano fish are not too many for a 10 gallon.

Neon Tetra Disease | The Aquarium Guide


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## cakes488 (Dec 2, 2015)

RussellTheShihTzu said:


> Neon Tetra are very sensitive fish and especially to water hardness as they are soft-water fish. That could be your problem; it also takes time for water hardness to kill. Were there any symptoms at all? Are all of the Neons nice and fat? Are they eating enough? There is also something called "Neon Tetra Disease." I've linked some information below.
> 
> I doubt your female is killing them; few fish/shrimp succumb to Betta predation unless they are already weak.
> 
> ...


Does water hardness kill Betta or effect them in a negative way ?


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## ThatFishThough (Jan 15, 2016)

cakes488 said:


> Does water hardness kill Betta or effect them in a negative way ?


No. They are better off adjusting than having you tamper with PH & hardness.


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## cakes488 (Dec 2, 2015)

ThatFishThough said:


> No. They are better off adjusting than having you tamper with PH & hardness.


I won't tamper...I haven't tampered since I was a teenager/young adult. I was constantly putting PH up or down in my tank....the poor poor fish. :shock:


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## RussellTheShihTzu (Mar 19, 2013)

cakes488 said:


> Does water hardness kill Betta or effect them in a negative way ?


I don't know. When dealing with Betta you have to remember they are more "lenient" about parameters than other species; they have a greater range of safe pH, GH, etc. If my water were extremely hard or extremely soft I would have no problem adjusting it.


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