I dont know whats wrong with my VT. He is not looking 100%. Hes still eating but is not as active as he should be and his back end is to skinny.... could he have brocken it???

Here are some pictures:

(I know the surface is scumy i have moved him to another container.)




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He does have a funky kink right behind his dorsal. Did he have that before? The kink looks like a birth defect to me. He swims okay, doesn't he?
Do you have any idea how old he is? Maybe his metabolism isn't what it used to be.
Looks like he could put some weight on. You mentioned he's eating. Does he eat everything you put in. I have a friend that has a veiltail that eats slowly. Not typical. It might be because the room she has him in isn't the warmest. Sometimes he doesn't get around to eating all the food before it falls out of reach into the marbles. I have a HM that is having a hard time seeing because of the opaque covering his eyes. I have to show him where the food is by sticking my finger in the water to get him in the general area. He had the same thinning out in the back half of his body until I started showing him where the food was.

Hes eating maby 1 or 2 blood worms or pelits that is see and then I move on to the next fish.

Whats a good food to put weight on?

Just a variety of foods. I would suspect that if there was something in their diet that was missing and all your bettas have the same diet that they would all be getting skinny. Mine seem to like variety. I like trying new foods, so I have a big variety. I've got a couple different frozens, a couple different pellets, some crumble, several freeze dried, and a couple flakes. They range from high meat protein to veggie to spirilina. In the summer I collect mosquito larvae and toss in a bonus little bug here and there. It's not really necessary, I just do it cause I get bored with food easily and figure they might also. How many times do you feed them each day? Maybe just an extra bit of food each feeding would help. Another idea would be to move him to a warmer location. The warmth will speed up his metabolism so he is able to absorb more nutrients from his food. The bulkiest betta I have is a veitail named Jack, short for Hungry Jack. He's the luck guy that lives in my feeder guppy tank. In addition to getting his regular feeding he snatches some of the guppies food and of course a new born guppy here and there. He's getting up there in years and is still looking good. Of course, he gets plenty of exercise chasing the guppies.

Normaly 2 times a day.

Twice a day should be fine. He might not be as active because he's bored or doesn't have as much energy. The reason for not having as much energy could be age, temperature, not enough to eat, or internal parasites (which I'm not thinking is a reason at this point). Keep us updated. Hopefully you can fatten him up a little. He looks like he has a nice place to live with his floating plants, pretty marbles and a neighbor!