Divided tnak's are not that bad, The biggest problem I found is a film get's built up on the surface of the section's without the filter.. I had 2) 10 gallon tank's with 3 lee's aquarium divider's, which gave each fish a 2.5 gal section to siwm in. I put gravle in each section & plant's plus decor... And like I said I didnt really have a problem with fish flaring or stress strip's, just the stuff that built up on the surface. So I went and got 2 sponge filters plus a gang valve and put them in each end section and everything was good to go, no more film on the surface and I also could control the flow in each section so the boy's were not getting thrown around..
I LOVE divided tanks. If you do it right I think it looks good and it's nice to have far fewer tanks. I have a 20 long divided into 6 and a 10 gallon into 2. Certain fish can get stressed and tail bite (personal experience) while others don't mind and make massive bubble nests (personal experience also). My 8 boys have always been in divided tanks, they do flare occasionally but not enough to stress them out.
Thanks to everybody for posting...I have learned a lot. Please keep going with your responses, It's helping me decide what to do with my two divided tanks! Maybe I should have made this thread one of those "voting" or "poll" types?
There are a few ideas on "obstructing" the bettas "view" of the neighbors...putting in some plants is one suggestion I heard and black solid plexiglass with small holes drilled for circulation, it obstructs the vision more than the embroidery cloth and should result in less flaring and stress.
I really love my divided tank. Cleaning is so much easier! And I like the way it looks, as long as it isn't 'cramped' (like when my 10 gallon was split into 5!)
Some of my bettas flared constantly at each other the first few days-you can obtstruct their view with plants. Some bettas don't like it, though...they get stressed and can tail bite. It really depends on the betta.
Right now, though, the two I have only flare at each other if they pass by one another by chance-but it keeps them occupied.
Both of them are quite happy. Othello keeps trying build a bubble nest, but the filter unfortunately ruins it.
The only problem I have is that filtering isn't as effective on the side that doesn't have it. You also have to make sure the divider is secure and that the bettas don't have room to jump over the divider!
A lot of the posters here have discussed the fin rot and biting fins problem. I was a victim of those, or one of those problems. I wasn't sure which problem I had until I posted pics on this site. Some of you helped me to recognize which was what?!?! Well...to make a long story short...the problem I had was hard tap water becoming even harder as I did water changes. Once I started "mixing" RO water and the tap water, to reduce the "compounding" of hardness, the fish rejoiced! You can almost see it in their "posture." I live in the San Joaquin Valley of California, most all the communities in this agriculture rich area use wells to supply their municipalities water. After all the years of farming the ground water is VERY HARD...as I continued to do frequent water changes, the tanks hardness slowly increased, to eventual levels that were disturbing the fish. So...by diluting the tap water with RO water I can keep the hardness down. It seems the fish were telling me the water was too hard by biting their fins. Thank you folks for helping me resolve, I think, my issue. BTW all four bettas are showing new fin growth currently. Thanks again.
Don't claim to be a hydrologist...just lettin' you know what worked in the bettas tank to stop the tail biting...when I used the RO water to dilute the hardness (and whatever else may have occured) of the tap water, the fish have stopped biting and all four have new fin growth. Whatever gets you to the desired result!
Berk: I live in Fresno (clovis actually), and we have horrible water in my area as well. I treat the water with.... shoot I can't remember, I'm at the bar, so I will check when I get home for ya. Also, when I first joined the site, a few people reccomended leaving your water out for a day or two before you do your changes. Atho I never had any problems before I left the water out, I do it anyway, and have no problems with it.
As far as divided tanks, my 10 gal is divided into 2, with one boy on each side, and have had absoluetly no problems with it. I actually divided it with a plyable divider I found at petsmart for just a couple dollars. (Again, I don't remember the brand or type off the top of my head, will get that info for you when I get home). It's fully breathable, the water can flow freely from through it. My boys can see eachother, but not fully, as it obstructs their views to just shadows of eachother. I have 1 sponge filter and 1 heater for this 10 gal, and have never had problems with alge, film, or other unwanted stuff. They're both happy and healthy.
I have 2 other fish in smaller tanks, 1 boy and 1 girl, all in top of my dresser. They can all see eachother, and they all regularly check each other out, maybe an occasional flare, but that's it. I'm 100% happy with my divided tank. I'll get some pictures later tonight.
Usally when they tail bite, It';s either a sick betta or a mutation in the gene's of the fish, which you wouldn't want to breed and pass on. But if R.O water fixed your problem great. But hard or soft water will not have a problem on fish they adjust there blood and liver to the hardness...