yes they have to cus if they didnt then there woulnt be any. i just wonder how they do it No, they do not regenerate. They breed. Males are typically the only ones sold in pet stores and they do have aggressive tendencies...but not towards the female they're trying to mate with.
There is betta food on the market, and if you should purchase this food the fish is not going to gulp this down right away. Bettas do not eat like we do, they go for days without eating it is best not even to try to feed a betta every day, one way to know if a betta is hungry or other fish is too watch them in there habitat, if the betta or your other fish are around the top and very active drop some food in, if they or it is just taking life easy do not feed them or it.
Place your tank in a desired location (preferably near a window) Have some gravel on the bottom of the bottom of the tank so that when your turtle poops, it isn't so obvious. Get a brick or a floating log or something so that your turtle can get all the way out of the water (it doesn't have to be huge, leave some space for your turtle to swim). Have the water deep enough so that your turtle cannot touch and is able to swim freely (give your turtle plenty of swimming room) Make sure you have a heater that is appropriate for the amount of water in the tank and a filter to circulate the water and keep it clean. That's about it!
A window won't provide even a little adequate lighting! Glass blocks UV, which a turtle NEEDS. Land should be about 1/4 of the cage and should be under the UV and heat bulb. For UV and heat, use a mercury vapor bulb, like Zoo med's Powersun. The cheapest you'll find any mercury vapor bulb that emits UV is $30. Any lower and it's the wrong one. If you think that's too expensive and your pet will be fine without it, then first of all, it may seem fine... until it dies! Really that's how it works. Also, if this is too expensive, that's not what being a pet owner is about. Pets are a commitment monetarily and timewise, treat them like one. Also, you need a good filter (for a 55 gallon, that will be about $75. Don't force it to swim in its own feces. Just because you can't see the feces in gravel doesn't mean it's not infecting your animal. Be prepared to spend a good amount of money on this pet, it's not just a glass tank with some water.
Fish tank yes? Did you clean the gravel?
Fish are only supposed to be fed once a week. It will eat when it gets hungry. It may still be digesting a big piece. My pellets that I feed my beta are a good size and he only eats 3 out of the 5 I put in there anyway.