I make my tank dividers out of clear craft plastic from hobbylobby(craftstore) it comes in different sizes. I buy a 24" x 36" sheet for 5.99 and cut it to fit the sizes I need. One sheet can do 2 10 gallon tanks, divided into 4 compartments, so 4 fish with 2.5 gallons each. I buy report covers with the black sliders at an office supply store around $2 for 6 sliders. So I can make the dividers at a cost of $5 per tank. I like to make these because their see thru and the fish look like their actually swimming together. An added benefit is that I can place the filter in the middle and have it flow into all 4 compartments. No baffle needed, everyone gets filtered water.
1. cut the size I needed for the length and drill holes all across the top (about 4 rows 1/2" apart)
2. slide the plastic report cover sliders onto the edges. makes a smooth clean edge.
3. cut 2 pieces for the front to back one on one side of the enghtwise piece and one on the other side.
4. drill haoles all over those 2 pieces and slide the black sliders onto those as well.
5. put the lenghtwise divider in then the front and rear pieces.
6. cut the plastic according to where the filter will be placed so the divider can be placed in the middle of the outflow. dont foget to cut behind the filter so fish cant swim thru the back of the filter.
I usually put the gravel or sand in first because it helps to hold the dividers into place on the bottom. when i add the filter in the middle, i make sure the outflow is in the middle of the two dividers. so it will flow half on one side half on the other. and that flow will flow into the 2 front compartents thru the holes you drilled at the top. also, make sure that you put a piece of plastic canvas or plastic over the tops so theres no way to jump into the next compartment.I have 2 pieces of mesh used to cover the tops of two of the edges so they cant jump, my lid keeps the front and rear separate. The plastic pieces can be placed to where their straight unlike mesh canvas where its usually bowed to stay in place. these are held in place by gravel and fit measurements. I have 2 pieces of mesh at the back of the hood so they cant jump from the rear.
This is actually easier than it sounds, a little time consuming, but, well worth the end results I believe.
Designed like this: theres better water filtration, easier to decorate, looks prettier to see the fish across the tank lenghtwise versus front to back.
feel free to ask any questions.
Heres a pic from the top inside the tank
and a picture from the front