Could I sandwich a piece of copper in between two pieces of silver or viceversa and then sumerge the device into water to achieve a production of COPPER IONS?? This example is similar to plates in the car batteries which is how I came up with this idea.

The Copper ions which is toxic to algae growth , which is gradually killed off leading to an effective method of cleaning a tank of green algae water.

Is this scheme feasible??

That only works if  you have the chemicals readily available! How am I going to obtain these chemicals?? I am trying tio make a device which can be made with simple evreryday household materials. If this device does produce COPPER IONS,then think of the possibiliites!!!

arent they more like blueish?

anyway, if u want to generate some copper ions through the method u first mentioned, u'll need 2 electrodes, an inert one at the cathode (something that can conduct electricity but not dissolve in water, example is graphite) and copper at the anode.

connect a battery with the cathode connected to the negative side of the battery (-) and the anode to the positive side of the battery (+)

copper ions would be formed at the anode (u shld see the anode "dissolving" in water. for the cathode, hydrogen may be produced, so be sure to keep the cathode out of harm's way.

Yeah for sure get the fish outta there before trying anything too risque.

arent they more like blueish?

It really depends on what compound you're looking at.

Copper oxides are generally the reddish/brown/black colours.  

I know hydrated copper (II) sulfate is blue, anhydrous is a whitish powder.

Copper chlorides are green for sure.

Umm...haven't really worked with copper that much, also the green roofs on top of old buildings are copper too.  I can't remember how it happens...I THINK it's a copper carbonate?

Lol but then it would be a physical change instead of a chemical one.

You'd probably end up hurting the fish in some way when all's done.