Dorsal fin disaster

[txbettaowner]

So I introduced my healing crowntail back in with the other betta females and I noticed that 4 of my other female bettas have fin problems. Their dorsal fins also are missing pieces and look shredded along with their anal fins and tail fin. What is going on? They couldn't still be fighting. The only female not messed with is my one veiltail ruby who was the aggressive one from the beginning but mellowed out or so I thought after 24 hours of introducing them. What should I do? Not to mention that my healing female is not shredded again and I let her bob in a cup in the tank for a few hours before releasing her back with the rest. Am I going to have to separate my one veiltail Ruby from the rest for good?

[callistra]

How do you know they're not still fighting? Are you monitoring them constantly? If you've got 4 girls chewed up and one that you know to be dominant spot free, I'd say it's pretty likely she's still picking on them.

What kind of filter are you using? If you don't have it prefiltered the intank tube could be causing issues. They could also be shredding it on things.. have you done the nylons test?

Have you tested your water or ammonia nitrites and nitrates? What is the size of the tank and how often/how much do you do a water change?

I know sometimes put sororities in smaller tanks, but at least 20 gallons with 6+ girls seems to work out best. Bettas need to be added all at the same time, and potentially cupped, held and repeat.

Have you seen the sticky that dramaqueen wrote? http://www.bettafish.com/showthread.php?t=29402

[txbettaowner]

I am not watching them constantly but I do check on them 3x a day or more as I feed them and randomly check on them. I am one woman who actually talks to the fish like they understand what I am saying lol I am using a Tetra filter. The tank size is a 10 gallon tank. I have not tried the nylon test. Why would 4 of the females be torn but my one veiltail is not? It doesn't make sense.

[txbettaowner]

I do 100% water changes weekly.