Oh I can certainly sympathize.....I had a REALLY difficult time with my boy Legolas. In all my years and in all the fish I'd had, I had NEVER had such a finicky eater before. xP
Sadly, frozen bloodworms don't fully meet a bettas nutritional needs.....as much as they like them, they're really more like betta candy. Great as a treat a couples a week, perfect for some variety, but very lacking for a staple diet. :/
You're going to have to get tough with your boys. I know its hard, but I also know from experience that you can eventually get them to eat pellets. It may take a couple of weeks of them not eating, but they will eat their pellets.
Now, what brand do you feed your others and how much do you usually offer? Have you tried soaking your pellets in a little garlic juice to entice appetite?
You may have to switch brands....out of the four brands I tried(HBH, Aqueon, Omega One, NLS)Legolas would only eat the NLS, and all of my fish disliked the Omega one. You may need to try a different brand or two.
What you're going to want to do though no matter what is quit feeding bloodworms. Offer them only pellets and remove what they don't eat after a while. They can go several weeks without food, so don't worry, its not going to harm them....and eventually they will get hungry enough to eat the pellets. Its tough love, and its not easy, but it is for their own good.
Once you have them eating pellets regularly, you can introduce the bloodworms back into their diet. ;)
Blood worms are not good for their staple diet, they're only supposed to be fed as an occasional treat. So . . . I would fast them for a day or two, offer a pellet, if they still won't eat it you can fast some more or get a different pellet. Mine are eating the New Life Spectrum pellets with the exception of my CT male who can't seem to eat pellets so he is getting Omega One flakes. They all get frozen foods in place of the pellets/flakes once or twice a week with fasting on Friday.
Do you have different brands of pellets?
My one betta stopped eating the pellets I had before, so my brother picked me up some Aqueon pellets (they were out of the Omega One) and he attacks them. They are also much smaller and easier to eat than my last ones.
My new betta loves the Aqueon pellets too, but I just got him on Tuesday and who knows how much they actually fed them at the pet store.. He's also considerably smaller than my other betta but neither have trouble with the pellets being too big.
My female is like that. It took me quite a few pellets and garlic juice before I found a pellet she liked. She LOVES flakes. I use Hagen's Betta Max Granule pellets. Those are the ONLY kind she will eat. She doesn't get really excited about bloodworms, but she will eat them. Flakes on the other hand, she goes crazy for, so she gets her favorite, expensive flakes once or twice a week as a treat.
My male seems to be happy with the pellets I've been giving him and he loves bloodworms. I haven't tried to feed him the expensive flakes yet, so I don't know if he likes them or not.
Yeah, I hate starving them. But I know those pellets have a combination of all the nutrients the fish needs. I have two different pellet types (I think of of them is hikari, the other I don't know) and my male bettas seem to hate both of them. LOL
The Hikari brand has within the past year or two changed their formula to include more fillers.....so unless you have the old formula from a few years back, they're really not all that fantastic quality-wise. I've heard they are also a little on the large side, a pickier bettas is defjnitly going to turn their nose up at that rather then try and pick at the pellet IME/O.
Before you jump into buying flakes, I would highly reccomend you try either Omega One or New Life Spectrum pellets. They're a little smaller, and NLS I belive even makes an even smaller pellet, and they're a higher quality win more fish/meats and such. NLS also has garlic in it, which might make them seem more appitzing to your picky boys.
I personally don't like flakes. I'm afraid to give them to my bettas in case they like them better and stop eating the pellets, lol.
That's why it took me so long to find a pellet she liked, since they had been feeding her flakes at the pet store. The only pellet she will eat is the same brand as her flakes, so I imagine they taste quite similar. They are both packed with fish protein, so I'm not worried about feeding her the flakes (they have better nutrition in them then most pellets), the only thing I really don't like about them is the mess they can make if she doesn't eat them all (which is rare, but a few do make it to the bottom, even then, she'll usually go after them).