Hey guys I know I am late on this discussion, but I found this thread and I want to post it. BatCakes I hope your betta doing wellJ
Tetra betta is really a horrible pellet brand. Its basically mostly all fillers like wheat and soy, which are difficult for a carnivorous betta to digest and really aren't all that tasty. Tetra betta has been refused by the fish of probably at least half of the keepers who have fed this that I've read about, even if your betta is the tiniest bit picky they're not going to take to it....and since you've already spoiled them on bloodworms, you're not going to get them to eat this brand probably.
I would very highly suggest heading over to your local Petco/ordering online some New Life Spectrum Betta/Small fish formula pellets, cease feeding of all other foods, and get them on that as a staple diet(as I described in one of my previous posts). Never had a betta who refused NLS(its nice and small, has a few good meats and meat meals up nearer the top then most brands including the first two, and includes garlic to promote appetite and has some anti parasitic properties), and have only ever heard of a couple rare cases where they did.
Once they are on a good pellet, you can certainly incorporate the flakes/frozen/freeze-dried foods back into their diet for variety(which is always good), but a good pellet as a staple is important to keep their diet well rounded.
Also, be careful with the Omgea flakes...I've read a lot of things about bones being found in them, which can be dangerous. Lately I've also been reading a LOT about the somewhat iffy ingredients in Omega products(I'm afraid I don't have any links right in front of me, but you can do a search of the forum/google and find a few things if you're curious), so I'd be cautious of them over all. Not saying you should just throw it all out or anything, but it never hurts to be aware.