I heard a lot of people said petco king betta are giant betta which is false, i dont know why petco call those round tail king betta, this make a lot of confusions for some. I will just call them round tail betta or fighter. Their price should cost like a regular round tail plakat disregarding their size.
I breed fighter betta and they have 2 size, medium and large size. Those king betta from petco size look just like my 5 stars fighter large size except that they are less aggressive than the real fighters. I'm not here to talk about my fighters but to make things clear. Real giant betta are 2.5 to 3 inchs when they are about 5 to 6 months.
So, petco king betta are not giant betta.