Crazy Betta Sorority Death

Of my 8 years of keeping various fish, this is probably the worst/weirdest occurrence ever to happen. I have a 20 gallon Betta sorority tank. It’s 2 weeks old today. All the bettas were doing great. No aggression other than establishing hierarchies and what not.

Today, I came back from work and could only see 5 of my six fish swimming about. I assumed the sixth one was hiding, though it’s usually active. I just checked my tank and noticed a white “stick like” object pinned in the gravel, facing vertically. After investigation, I saw an eye socket and realized it had to have been a Betta. I take it out and realized this girl was DESTROYED. Easily beyond the capabilities of a Betta sorority. I mean, there were no fins on the fish, just a bare white body (her body was blue). No eyeball, no organs. The body has a hole, and is completely hollow. I’m beyond belief a frankly dissapointed, she was the prettiest girl.

My tank has:
6 (now five) female bettas, all similarly sized.
1 Female GBR (her husband past 6 months ago, she’s still standing)
One Female guppy
A school of otos
Lots of ghost shrimp and nerite snails.

Any ideas? Help please! Thanks!

 

Ive never had luck keeping a sorority, and fish will absolutely rip other fish to shreds if given the chance.

Ive had sororities that were in tanks so heavily planted you could only see green. 8 months of perfect harmony, then killing sprees. There is no rhyme or reason other than its not normal for multiple Bettas to inhabit a small tank. In the wild, they can get away. In a tank, they cant.

 

You would be amazed what betta are capable of.

 

Ive never had luck keeping a sorority, and fish will absolutely rip other fish to shreds if given the chance.

Ive had sororities that were in tanks so heavily planted you could only see green. 8 months of perfect harmony, then killing sprees. There is no rhyme or reason other than its not normal for multiple Bettas to inhabit a small tank. In the wild, they can get away. In a tank, they cant.

Should I be worried for/expect another killing to happen?

 

All the fish you have will chow down on a dead fish, she could have been killed by another betta or passed on her own.
Her being hollow and eyeless points to the bottom dwellers and the other fish for having to eaten her - fish will not pass up a sushI meal if given the opportunity, even cannibalism eating.

 

Probably. That's what happened in mine at least. Once one turned, it caused a chain reaction. And these were all BABIES that were SUPER docile and friendly, raised together, no problems ever. The dominant one almost killed the second in line, then the second in line turned and so on and so forth until I split them up.

And Mcasella is right. Fish eat fish. If it were injured, dying or dead, the others will just go crazy and feed on it.