Aggressive Crowntail Betta - Should I Give Up?

[zanac12]

Hello,

I bought a crowntail betta about 3 months ago and he is doing fine. He was about 6 months old from what they told me at the pet store (so 9 months now), dark blue fins, blackish tips.

Just recently I wanted to give him some company…but disaster occurred!

First he killed a goldfish, then several white clouds, 2 neon tetras, and even bullied a poor small snail. He even started attacking a female betta, (my last resort for him). He seemed like a pretty friendly fish before all this, and would seldom flare at my finger or at any objects that I put near him. I don’t get it…why is he getting aggravated all of a sudden?

I want to give him some tank mates, but he keeps killing them all off.

So is this one meant to be alone? Why do other bettas not seem to mind company, and he does? Is there anything I can do to cool him down besides throwing in an even more aggressive Oscar? Lol

(10 gallon tank, plenty of room, plants, filter, levels good, eats very well)

Thanks!

[Hanul]

When you add a fish to the tank, you should remove him and move the plants around first... then add him later. He may just be territorial... so making his environment different may help.