tattered tetras?

[n8tr_lvr]

Hello,
I have a 20-gal long tank that is the current home to:

1 mild-mannered male betta
5 neon tetras
2 cory cats

My concern is the tetras.....they look like they have been in a street-fight. Their fins are torn and one looks like it has scoliosis (though I believe it came from the pet store that way). The fins on the veil-tail betta are beautiful, not tattered at all. The corys look fine as well.
The water conditions are fine, checked regularly. And I do regular water changes between 10-20% each time. If water conditions were a factor, I'd expect all fish to have torn fins. There are plenty of plastic plants and decorations to hide in.
I say the betta is mild-mannered because I have never seen him charge, chase or attack any of the fish in the tank. He doesn't even "puff-up" if he sees his reflection in the glass. So I don't think he is picking on the tetras.
Any help would be greatly appreciated.
thanks!
Nic

 

[Luananeko]

How sharp edged are the plastic plants? Is it possible that the tetras are cutting their fins on them? If not, maybe the cories are bothering them?

 

[sheilashoelady]

The betta may be nipping at the tetras after lights out. I think if it were the corys (highly doubt it) the bettas fins would be ripped also. Same for the decorations, especially since bettas have long flowing fins.

Sent from my SCH-I545 using Tapatalk

 

[Luananeko]

Bettas usually stay much higher in the tank than the neons do, so I wouldn't rule out the cories. If the plants are shorter then the betta may also be steering clear of the sharp leaves. Hard to say without seeing what the layout is.

 

[n8tr_lvr]

How sharp edged are the plastic plants? Is it possible that the tetras are cutting their fins on them? If not, maybe the cories are bothering them?

The plants are mostly the rounded-edged plastic plants. The betta's fins are fine, not a split end on them (and I have had the betta for 1.5 years already).
Are there better suited tank mates for the betta?
-Nic

 

[Cynic]

Based upon your stocking I'd have said it was 99% likely the betta is to blame.

 

[venymae]

I'd guess the betta or neon in-fighting (but still the betta is my first guess). I have quite a few pokey plants in with my neons and they have never torn a fin on them.

 

[Luananeko]

The plants are mostly the rounded-edged plastic plants. The betta's fins are fine, not a split end on them (and I have had the betta for 1.5 years already).
Are there better suited tank mates for the betta?
-Nic

It really is dependent on the betta personality. Most bettas I've had were okay with tankmates like the ones you listed, but you run into some that get stressed or annoyed by the activity of a community. It may be that your betta is one of the latter ones. He may do better in a 5 gallon by himself or maybe with one bottom dweller like a snail or frog. Normally I'd suggest a shrimp too, but if he is indeed bothering the tetras then a shrimp might be targeted too and wouldn't be as resistant to its harassment like a snail or frog might be.