I bought this male betta yesterday, and he still won't eat. He just spits it back out, and the flakes sink to the bottom of the tank. My female that I got along with him eats just fine. He also just sits around and barely moves. Buffy (the female) swims around and everything. I also think that he may have fin rot, but I'm not for sure since I'm new to this whole betta fish thing.
Here is Axl.
do you only have flakes? some don't like flakes, but if you have pellets soak them in garlic to make them more appetizing. if he still won't eat, give it a few days. eventually he will get hungry enough to eat. it sounds cruel but give him food every day and see if he eats it.
Either way, pellets should be a staple in their diet, normally they tend to be a little bit better for them. Presoak them if they are too big for him to eat as a whole.
Bettas can take up to a week or more before they eat healthily when introduced into a new home. They can live up to 2 weeks before they starve, and in the wild they will skip a day or two every so often. Flakes aren't usually used to feed them in pet stores or breeders, etc, so sometimes they are foreign to them and they are unsure how to eat them. As mentioned before, make them small, and only feed a tiny amount. Flakes will cause the water to get dirty quickly, so make sure you do regular changes depending on size/filter of your tank.
Another question off topic.. your male and female aren't housed together, are they? If so, separate immediately, one will kill the other and that can also be the cause of lack of eating from stress.
As far as his fins, hard to tell in that pic. Are the edges black with shredding? I don't see the black edges. I do see the fin curl on top. I have one like that myself and he's as healthy as can be. I've tried the salt treatments, etc but nothing has worked. As long as you do the appropriate water changes, he should be fine.
Are you worried because of his top fin or are there other reasons? Here is my Xander and his curl. Sorry, camera got blurry when I got close to him.
If you can get a side view picture, that would be great. =) A missing spot could be decorating or a self biting session (bettas will eat their own fins when they are either bored, or placed in a new home that is larger then prior because their fins are heavy and they haven't developed the strength just yet to swim so much more). Or it could be fin rot if accompanied by black edges. If you see crusting, fraying, shredding, tattered, fuzzy on the black parts then you will need to do treatments for finrot. Just make sure he has it first, using the AQ salt too much can cause him to become immune to the benefits it has for them.
1tsp per gallon of Aquarium Salt, do 100% daily water changes, for 10-14 days. You can keep him in a smaller container if you wish to make it easier on you. A 1gal or such. Make sure you dissolve the salt prior to putting him in it, letting it site for a half hour and shake it up/stir it, otherwise it will burn him he if touches the salt grains. Stress coat (bought at all fish stores, walmart, etc) will help fin regrowth. (plus has other benefits so it's good to have on hand and use)
Do regular water changes, unsure how big your tank is so can't really say how much to do. But clean water is all it takes to prevent such things from happening. Sadly, you just never know what you bring home from pet stores sometimes. Good luck and welcome to the forums!
It looks to me like he's got a little chunk missing from his tail. Is that what you're talking about? He may have gotten it caught on something. Clean water is the best thing for finrot if that's what he has.