It may be trying to attract another fish to breed or it may simply be dying. That depends on the species of the fish and the type of "wiggle". The basic rules of fishkeeping are. :- 1 inch of fish needs at least 1 gallon of water :- Every tank needs a permanently running cycled filter. (This converts deadly Ammonia into none deadly Nitrate):- Every tank needs at least 50% of its water replaced every week. (This prevents a build up of excessive Nitrate.) Follow the above rules and your fish stand a chance. Fail in any of them and I can guarantee that your fish will be constantly getting sick and will live a shortened lifespan
Becasue that is the body movement they make in order to swim and when they are caught their instinct is to try and swim away, just as people try to run away from danger.
Some fish prefer swimming at the top of the tank while others the bottom or middle.
It's sick and/or dying.
they just settle at the bottom of fish tank
it means they are most likely dead or going to die
gravel
This may mean that you are over feeding your fish and they cannot finish what you have put in the tank; reduce the amount of food you give each feeding, and make sure you clean the tank regularly
I suggest that you learn more about your fish in your aquarium. One of your fish might be a bottom sucker which means that they eat all of the dirt on the side or bottom of your tank. If one of your fish are bottom suckers, that's probably the reason why your aquarium is clean. If none of your fish are bottom suckers, than somebody must be secretly cleaning your tank for you.
That refers to where the fish eat; near the surface or towards the bottom of the tank.
This may mean 3 things: # It may be tired, # It may be sick or injured, # Or it could be near the end of its life.
It dies
Fish eggs, fish sperm, mold.
food flaots