People have kept fish as pets in aquariums since the days of ancient Rome. We have, of course, progressed since then on what our ideas of fish health are. It is not healthy for certain fish to be kept in the same aquarium due to the aggressive nature of some fish. Having more than one tank, however, can start getting expensive really fast. Using some store bought materials and common tools, you can build your own tank divider and keep your fish separate in the same tank.
Measure the dimensions of your fish tank. You will need to get a measurement for the width of the tank, and for the water depth. Measure from the bottom of the aquarium to where your water level will be for the depth measurement. Now take your measurements and subtract 1/4" from your measurements. This will allow the divider to easily fit into the tank.
Use your saw to cut out seven pieces of PVC pipe. You will need 1 piece (horizontal) that equals your final measurement (measurement minus 1/4") for the width of your tank. You will also need 2 pieces (vertical) that equal the final measurement of your depth measurement. Also cut out 4 legs for the divider. Each leg will need to be 8" long. A vice would be useful, but not necessary, for this step. Use safety goggles for this step.
Use the utility knife or sandpaper to deburr all of the cut ends of the PVC pipe.
Use the PVC elbows to connect the two vertical PVC pieces you cut to the one horizontal piece. The vertical ones should be pointed in the same direction. Attach the two PVC tees to the bottom of the vertical pieces. You should now have an object that looks like 3 sides of a square.
Test fit this piece of the divider in your tank. If the elbows or tees cause your frame to not fit, measure how much more PVC you need to cut off. Then take apart the frame, recut your pipe, and reassemble the frame. When you are sure that the frame will fit into the tank, remove the frame and put the legs into each side of the PVC tees.
Cut your egg-crate material using the diagonal wire cutters. You will need a square shape that slightly overlaps your frame. You will also need to cut out a small square on both sides of the egg-crate that will be located at the base of your divider. This is so the material will fit over the PVC pipe legs. This will usually only require cutting out 4 of the small squares in the bottom corners.
Use the cable ties to fasten your egg-crate piece to your frame. Use one tie at each corner of the frame, and one in the middle of every section. Make sure you put the small squares you cut out at the bottom of the egg-crate material are at the base of the frame. Cut off all excess tie using your wire cutters.
Remove the gravel from your tank. Remove the "legs" from your frame as well. Put the tank divider down into the tank where you want it positioned. Re-insert the "legs" and replace your tank's gravel.
Allow the water you put in the tank after inserting your divider to get to room temperature before reintroducing your fish.
You may harm yourself if you do not use goggles while cutting the PVC.