Well, now I have 2 tail biters, I can keep them together in a divided tank in my special tail biting formula I am sure it is the excessive finnage that makes at least some of them do it. Dumbo is a RT, and the new fish is a DTHM. I did think it was the stress of shipping that may have coused the DT to have a munch, but the breeder sent an extra "replacement" pair with them, so it is obviously something he did before leaving Thailand.
I probably won't be breeding the DT with the female he is being sent with. She is DT as well, and his body is already a little too short. I bought him for his gorgeous blue/orange butterfly pattern. As for Dumbo, I want a pure big ears spawn before attempting outcrosses. The female is a little bit tail heavy, but can't find a long fin HM big ears female that isn't. I'll breed them, then work on a few outcrosses. If the trait doesn't get passed on to non big ears fish, then I at least will have some pure big ears.