A female betta (fighter fish) may get vertical stripes at breeding time, and horizontal ones if they are stressed. Fading colours usually means illness or water quality issue
Yes, they do, it happens from time to time. Some believe the changes in coloration are related to the gender of the fish.
changes with species.
They are spawning.
By the fish
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
Mosquitos
there black
Betta fish can change color due to genetics, stress, age, or health issues. It is a natural process for some bettas to change color as they mature. Stress from changes in environment or water conditions can also cause color changes. If the color change is sudden or accompanied by other symptoms, it may indicate a health problem that requires attention.
You Let Them Lay Egg In It
A fighting fish, just google it. It's pretty easy.