Every article I read says the Head and Taillight is a 'peaceful' community fish. He's nipped the tails off 2 of my fish and chases them around, any ideas?
What size tank do you have and how many do you have. Also what fish live with him. I have some with angels, guppies, and rasboras and they don't nip them.
Welcome to Fishlore
Those are schooling fish and frequently when kept alone can be quite nippy. You need at least three but more is better.
Glad to hear things have worked out. Yes Mr. Guppy doesn't care as long as he thinks its female but he will notice the Guppy females sooner or later and probably sooner
The Head and Tail Light shouldn't be in a tank with a Betta. The Betta will make an even better target for a lone tetra, with his long flowing fins, than the other fish did. Bettas and tetras are not considered compatible because the tetras will soon leave Mr. Betta tailless.
Tetras are shoaling fish and so they need to be kept in groups of 6 or more. Otherwise, you will have nipping problems. If you get your H&T Light some friends to play with, I be he'd be a much more peaceful tankmate. But he can NOT be left with the Betta.
Well, I still wouldn't recommend leaving him in with the Betta. I would hate to see you wake up one morning and find your Betta finless. However, even if you think the Betta and tetra will be ok together, the tetra will not be happy alone. Tetras are shoaling species so they need the company of several others of their species. Otherwise they will be timid, unhappy, and stressed. This is because in the wild their defence mechanism is to live in large groups. This goes for the Silvertip and the Serpae as well...they should be kept in shoals for their own benefit. This will also stop the nipping.
There have been several betta owners on the Betta board who have had trouble with the Tetras nipping the fins of their betta and eventually this WILL lead to infected fins and bacterial fin rot and can lead to death for the betta if not treated.
Also Tetras of all kinds are schooling fish and need to be kept in groups of 6 or more to avoid aggressive behavior. Your tetra is going to exhibit this type of behavior even more than usual because he is not in his normal living style. He is a bully and will continue to be one only you will not notice until the fins of the other fish are too short to be repaired without a lot of help and isolation.
Nipped fins are no joke and bettas have no defense as they do not see tetras as threats so they generally will simply let them do it. It is really sad that you insist in keeping these fish together.