Hi guys
I have a community tank set up at my work. It has some neons, a tetra, a cory, and a betta.
When the old cory (very old) was coming to his end, as a result of old age, the betta in the tank would pick on him. Then I got a new tetra. It was free He had jumped out of the bag that he was in so I think he got some damage to him. Anyways, less than 24 hours later the betta ate his head.
Has anyone heard of bettas attacking the weak like that?

i had a friend whos betta behaved like that. i have no idea why though.

bettas are carnivores. I should assume that they would pick off whatever they could as sustenance.

My g/f had a betta and 3 neon tetras in a 5 gallon tank for one day. the next morning, she had 3 dead neon tetras and a very pleased-looking betta.

They are very territorial fish, because of where they came from, and I think they do better on their own.

I one time had 2 female bettas in with some gouramis were fine. Then I got a few neon tetras... females killed 3 of them

So I saved the last one and took him back to the pet store...

Ah, not to be sadistic or starnge, but the way you worded this made me double take and giggle. Agressive bettas are very common, hense the name fighting fish, and will fight for territory as said. This applies to both other bettas and other fish.

im sorry i did too.. i was just sitting reading it and figgiting as you do, ya know wiggle ur foot or something and then i got to "24 hours later the betta ate his head" and i just stopped.. now i have the giggles..
i know it shouldnt be funny, im sorry.. omg i cant stop giggling..
im gonna shut up now.. sorry

how old is the cory? because Someone around here has one who is like 17?

My dad has an albino cory that is about 15-16 years old.

Bettas will eat neon tetras. I had some with a betta once and he killed all except one. For some reason he never killed the last one. Go figure.

I have never trusted any betta to live with other fish. I don't even know if I would try a female in a community tank.