How smart are fish ?

Fish are not intelligent at all, they don't need to be, they have instincts
instead of handling difficult decisions.
I used to raise fighting chicken. They are territorial and will defend its
domain to the death, literally.
You see, they have no choice, they will respond to a stimuli in the same way
over and over and over again.
So, if they get a response "starter" the reaction will be the same.
In the case of fish, well, they are a couple of steps down from birds in the
evolutionary scale.
They will be triggered by the reflection and will respond in the same way
for ever regardless of self-injury. Remember, animals don't know death or
that their wounds are not going to heal.
I visited a friend with a similar issue with a fish but he liked the
aggressive reaction of the fish. Well, I visited him two years later and
the same fish was doing the same funny reaction after an illumination
trigger.
But don't worry, as soon as they acknowledge its new "neighbors" as
harmless, they will go around and invest their energy in other things. Yes
they will comeback again but will not stay there for long. In the other
hand, if they associate the other fish with the pain they felt after the
hit, lol, you better change backgrounds.
iy

"Pszemol" wrote in message
...
I have a problem... in my huge wisom I have covered a side wall
of the fishtank with a mirror-foil. Just to cover the unpleasant view
behind of the tank... and to get some more light reflected back.
Today I let the fish in this new tank...

A pair of maroon clowns and hepatus tang get crazy seeing their
own reflection in the tank wall.

Now my title question: will they realize this is just a mirror
soon or they will continue to fight the other fish in the mirror?
How smart are they ?

It is difficult to take the foil off since it is in a tight space
between the tank and room wall... First day I turned off the lights
sooner and wonder what will the group advice be...
Should I go trought the trouble of removing the foil or the fish
will get used to this reflection soon ? If so, how soon will it be ?