Tail biting or fin rot? Help!

Hi guys. I really need your help.

I had a look in my tank just now to check on my bettas and I noticed that my gorgeous guy, Arlo has a massive chunk of his tail missing!

I’m really worried about him. I’m attaching pictures to the thread, can anyone tell me what this could be? I’ve not had him for very long, probably around a week now and he was hiding for most of the time for the first few days, he’s only just started to warm up to me.

I’ve checked my parameters, ammonia 0, nitrites 0, nitrates are at about 20ppm (a little high, I know. I’m working on it). He lives in a divided aqua one betta trio so he has around 2.7 gallons that he shares with a couple of amano shrimp.

Could it be fin rot? Or is it more likely to be tail biting? The other two bettas in the tank seem fine. If it is tail biting, what can I do to stop it?

Also how long can I expect to wait before it grows back?

Thank you in advance.

 

I don’t think it is fin rot because it happened so fast.. other than that I don’t know much. What is your temp and ph? Idk if shrimp could do that? Looks like a chunk taken out..

 

Yes, that is definitely not Fin Rot. It looks like Fin Tear and Fin Biting combined. From what I've heard, tail biting is usually caused when they are stressed in their current environment.

 

Thank you. Is there anything I can do to reduce the stress or causes of fin biting? I’ve already got an Indian almond leaf in there

 

Could he have gotten it caught on anything? Its not fin rot....yet, but the conditions are right for it to happen tho

 

Is he super active and does he like exploring? He may want a larger tank. Preferably 5 gallons or more. He also might be seeing his reflection somewhere.

 

I don’t think it is fin rot because it happened so fast.. other than that I don’t know much. What is your temp and ph? Idk if shrimp could do that? Looks like a chunk taken out..

Ph is 7.2 and the temperature is at a pretty steady 25c

 

Could he have gotten it caught on anything? Its not fin rot....yet, but the conditions are right for it to happen tho

There aren’t any decorations in there that could rip it I don’t think

 

Is he super active and does he like exploring? He may want a larger tank. Preferably 5 gallons or more. He also might be seeing his reflection somewhere.

No he’s actually a very calm fish, he doesn’t do very much and doesn’t flare at anything. He’ll swim around the tank slowly and also go through his cave, that’s it really. He’s the calmest out of all three that I have

 

No he’s actually a very calm fish, he doesn’t do very much and doesn’t flare at anything. He’ll swim around the tank slowly and also go through his cave, that’s it really. He’s the calmest out of all three that I have

Hmm, my cousin's fish bites when he sees his reflection in the glass. Usually because the light outside of his tank is way darker then the tank, apparently that creates a mirror.