You Let Them Lay Egg In It
They are spawning.
the male betta fish makes the nest.
The fish they stole were Japanese Fighter Fish
yes all fish have gills.
no way! they cant because chinease fighter fish are semi aggresive and will fight with your other fish or if the other is to big the gold fish will eat him
fish hit the ground with there tails
The water.
fighting fish
A betta is a nest builder, so it has built a nest, the water should be above 76 degrees, for it to build its nest, if you allow the 2 fish to join, do not be suprised if the male kills the female, you should watch the 2 fish if you care about the female fish, if they seem like they are getting along then you can leave them together for a while, you will know very quickly if they are compatiable,once you see that the female has laid her young and the male is tending too the nest, remove her, the male will take over the care of the nest. If you are intrested in breeding then you will have to hatch some brime shrimp, search the internet for breeding bettas. you will be able to print the information out,or write it down.
Mosquitos
there black
A fighting fish, just google it. It's pretty easy.