just another reference for ya. I have an all in one system, so my filter is in the middle of the tank (only fits that way with the hood). You can see in the pics below that i bent it around to give an eve amount of space for both fish.
Also the tank has a lip. I just cut the 90 degree angle out and measured so that divider would fit in there nice and snug underneath the lip on the tank. The upper part of the divider leaves only a 1/8" gap to the cover of the tank. even without a cover though, the divider is much higher than a betta could jump. keeping water levels a bit low is certainly a solution if you have a different setup.
This is a store bought divider, but I wouldn't recommend it due to price. Also, at the time i was concerned about the bettas always seeing eachother so i sanded it with high grit sandpaper so it wasn't transparent. They still catch shadows and see each other a bit and have "flare-offs".... but you certainly don't need to have an opaque divider..... i just thought it would be a good idea at the time.
top view so you can see the cuts and bend
only bonus with the store bought divider is it came with clips that hold the divider tight against the glass. nice alternative to having to glue and helps a flexed divider stay in place.
These are old pics. I have this tank filled with gravel now and buried the divider in it.
Just a little different setup than what other people have posted so you have some more ideas
Also the tank has a lip. I just cut the 90 degree angle out and measured so that divider would fit in there nice and snug underneath the lip on the tank. The upper part of the divider leaves only a 1/8" gap to the cover of the tank. even without a cover though, the divider is much higher than a betta could jump. keeping water levels a bit low is certainly a solution if you have a different setup.
This is a store bought divider, but I wouldn't recommend it due to price. Also, at the time i was concerned about the bettas always seeing eachother so i sanded it with high grit sandpaper so it wasn't transparent. They still catch shadows and see each other a bit and have "flare-offs".... but you certainly don't need to have an opaque divider..... i just thought it would be a good idea at the time.
top view so you can see the cuts and bend
only bonus with the store bought divider is it came with clips that hold the divider tight against the glass. nice alternative to having to glue and helps a flexed divider stay in place.
These are old pics. I have this tank filled with gravel now and buried the divider in it.
Just a little different setup than what other people have posted so you have some more ideas