Why is my fish's tail fraying?

Question

I've had quite a science lesson when I became an owner of two betta in May. I didn't know I was supposed to cycle the tank and both fish got tail rot. I got help through this forum. A few days ago, one tank finally cycled. I checked the water in the other and it too finally cycled also this afternoon (last week it had a low level of ammonia). So, now, I looked at my fish when I came home for lunch and noticed that his tail looks stringy. He is in the tank that cycled last week to no ammonia. So, someone had suggested tail bitting in another answer last week.... I am not sure. How can you tell the difference between the two? Also, how can he get Tail Rot if his tank is finally clear of ammonia? Plus, I just changed the water last night. So, his tail became that way sometime this morning. I have two 3 gallon tanks where my betta live in separately. There is a carbon filter in each tank. I change that every week when I change the water. I do a 25% water change weekly.

I have silk plants in my tanks. I don't see any sharp areas because I always check. No other fish in the tank.

Answer 1

I'll throw in a few other possibilities - 1) if the current from your filter is too strong, your betta may have swam too close to the intake and got his tail caught and that's why it's torn and 2) if you have plastic items for decorations, one may have a sharp edge that caught the tail and ripped it.

Really, any of these would be a possibility. In fin rot, it usually starts along the entire edge, not as a single split. See the photos in this link for an idea of what this looks like in the early stages: http://www.bettatalk.com/betta_diseases.htm Although it's associated with poor tank maintenance, the cause is bacterial.

If the tail seems more torn, check for rough edges or sharp points on objects in the tank. You might want to use silk or live plants rather than plastic. If there are other fish in the tank, watch their behavior from a distance. If you have schooling fish (tetras, barbs, danios) make sure they have a proper school of 6+ - otherwise that may nip fins of other fish as part of establishing their place in the dominance hierarchy in the tank - in a group, they usually keep this behavior between others of their own kind. And if your filter has a way to adjust the flow, try turning it down - this will also make it easier on the betta when he swims, as the long fins don't make swimming in a strong current easy for them.

Answer 2

Sounds like tail rot to me.
First thing to do is a large water change.
Since this is a fungal infection, medication such as Jungle Fungus OR Tetracycline OR Maracyn and Maracyn-Two combined together, along with sulfa-containing medications should do the trick. Follow the directions of these medications. Notice the ORs and ANDs, so you don't mix in all medication :) Also be warned that medicating an aquarium may kill your benefficial bacteria and trigger a mini-cycle all over again.

Answer 3

Your fish is sick.When the tails were rotting...K...that was a fungus...take them to a vet.