This can depend on what type of food you are feeding your fish. If you are feeding betta bites, then typically the fish would eat from the surface. If you are feeding flakes, then it's possible the fish is simply waiting for the food to sink.
It's not uncommon for fish to forage around the bottom for food that may have settled there.
you can teach them but its a little hard. my bettas can jump out of their tank and eat when i tap the glass. just ask me when ever you like! i know so much about bettas but i dont mean to brag.
Not normally, they will the eggs. Normally a turtle lays the egg and then leaves, but since its in a tank, they'll eat them!
No neccessarily. The male fish will usually eat any dead ova. He will normally look after good ones, pick them out of the gravel, and put them back in the nest until they become free swimming fry.
It depends on what species the frogs are. African dwarf frogs (which remain very small) are ideal tankmates for female bettas provided the tank is filtered and large enough for all the occupants. African clawed frogs are fine while young, but grow quite large and will eat the female bettas when fully grown; when grown they also need a much larger tank than the average betta sorority.
they eat left over fish food on the bottom of the tank (if in tank)
Mostly the algae that forms on the sides of the tank and the dead things on the bottom of the tank.
yes
If baby guppies are lying at the bottom of the tank they are dead. They tend to stay as hidden as possible in plants as the adults will eat them.
yes
Bettas will eat baby guppys as will most other fish, but in general, male Bettas will only fight with other male Bettas. They do not fight with other species of fish
They will both eat about the same.
Not normally, but if you have babies in a tank with adults they might eat them but probably not. Some eat their shedded skin though.