Seriously, this is driving me insane. I have two CT's - one is a DR, the other a DDR. Both live in 3 gal critter keepers that get 100% water changes once a week. I use a mixture of aged treated tap water and deionized water because I really can't use the tap water by itself (ammonia and hardness). My DDR's rays are perfectly fine, thick and beautiful. However, the little DR's rays have thinned out considerably and have become so brittle that some have broken off. It is only on his caudal rays though. His dorsal and anal rays are fine. What is going on? I know it is not fin rot. And I hope this little guy isn't nibbling on his tail. Any input/advice would be great.

i have had this happen to my older CTs. Was there by any chance a big change of some kind in his water? you should test it because the only things that can do that are aging and water quality.

I knew this was a question for gup lol !!!!!!!

I am just wondering if the deionized water could be the culprit.

I have had him for about two months now. I have always used the deionized and tap water mixture since I got him. All my bettas get this kind of water and don't have any problems. I cannot use my tap water alone because it tests about 1.0ppm ammonia and the ph is close to 9. The hardness is also through the roof. The DI water helps to dilute the ammonia and also lowers the ph. I also let the water age for at least 24 hrs and the ph drops even further. I always test the water in my containers before I do a water change to make sure the parameters are consistant every week.

I know if I used DI water by itself I would have to add something like R/O Right to put back trace minerals. By mixing it with treated tap water, I believe the the trace minerals are provided by the tap water.

I'm pretty sure this guy is young. He is a small guy. What really stumps me is why my other CT's rays are perfect. :blink: And why is this only happening to his tail?? Tail biting?

Right, that's why I thought there might have been something missing out of the water. Have you tried using IAL? He may just have needs for something extra. Of course you are right it could very well be tail biting.

I think some IAL should be tried...
Also, getting some good water in there might help...
Might try some spring water...
I dunno what brand, but I'm guessing there's some recommendations on here.
A little aquarium salt would help too.

Well, I'm going to order some BWE online soon. I'm also going to be adding the R/O Right into the DI water before I mix it with the tap. See if that helps. Spring water could be an option, but I would hate lugging around all that water. It's more practical for me to make the DI water at home anyways. I know a lot of people that have had luck with DI water in their aquariums because you can basically customize to your needs.

Before I went to work tonight, I think I caught the little guy nibbling on his tail. Not to sure, because he was hiding himself.

Thanks for all of your advice!

If he biting his tail, then get him a female and sit it next to his tank, he will forget about chewing that tail and it will make him happier in general, just go to LFS and get you a Cute VT girl, obviously don't spawn them, anywasy i always give this advice, plus its a reason to get a cute female :T it should help, I think they chew there tails out of frustration/stress and sometimes bordem, But Thats just my 2 cents. :D

Sometimes filtering a tank and giving them a mild current helps them not be so bored.

Once again, thanks for all your advice. ^_^ I'm still really not sure if he's biting, but he does have one of my girls next to him. I've never seen him flare. I've tried mirrors, the girls, and even the fish on the Hikari packet (my other boys will go nuts). He's a shy little one! I decided to add a little Jungle Fungus Clear just to prevent any infection. I have spotted some regrowth, and it seems like the other rays have stopped breaking off.

I've also decided to try mixing spring water instead of the DI water. My boyfriend's niece just got a betta two weeks ago and had some missing parts of fins. He is kept in a 50/50 blend of spring water and tap water. He has had some absolutely amazing regrowth! I am convinced it is the good quality water. Anyways, the DI filters are expensive to replace.

Anyone recommend any good cheap brands of spring water?

I bet he is nibbling his tail. My Sunti used to do it. I had his tank on my nightstand next to my bed and the activity of me being right there kinda over overstimulated him and made him nervous enough to nibble.He does have a filtered tank. I moved his tank over to the night stand across the room where he only sees me next to him once in awhile. His tail has healed completely. I also have some ial I use in his and the females water all the time. You can actually order some high quality ial on this site from LoVyDoVy. His nephew in law in Malaysia collects the leaves for himself ( he waits till they fall off the tree , collects them, cuts and packages them and sends them straight to you) I have ordered twice from him and the leafs are extremely high quality. PM LoVYDoVY about ordering them from him. I think they come in $5 or $15 bags. The others are right about salt. I use a little salt in my water all the time.
Has there been any recent changes to his tank or tank decor etc? Sometimes this stresses them out and makes them bite their tail. If you ever see him wrap himself around in a circle he is probably biting his tail. Also what kind of decor does he have in his tank? Is there something he could be damaging his tail on? Something sharp?
Also along with the ial and salt you might try some betafix ( a betta sized dose of melafix- can use melafix instead if you can not find bettafix) and it will help their tail heal. I had an elderly male betta ( 3 years old) and he needed bettafix in the water all the time or his tail would deteriorate. With the ial and bettafix his tail grew back in well.