first obviously they need to see each other but in different tanks if the male is swimming around in circles spreading his find then he is wanting to spawn if the female is going up to the side of the tank closest to the males side and showing off her color then the female wants to spawn this is not all you need to know to spawn fish so keep studying!
yes all fish mate
They are spawning.
Nothing special will happen to her. If she fails to find a mate once she is ready to spawn the ova will simply either remain in her body waiting for her to find one or they will be reabsorbed back into her body from where they developed.
The fish they stole were Japanese Fighter Fish
no. fish can only mate with fish of the same species. Gouramis mate with gouramis and platys mate with platys.
Do you mean will they mate with other fish or get along with other fish? They will not mate with other fish, but they will get along without tetras.
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
To mate fish, you should see how the fish you want to mate, mate. Then you should put them in the same tank and watch them. I'm not an expert so search the web for a more through answer.
of course, why not?
No.
Oscars are the breed of fish that mate the most. However, guppies and trigger fish also mate much more than other breeds of fish.