I've recently purchased a new Ancistrus Dolichopterus, a black female with small white/blue spots.
I already owned a male Ancistrus Temininckii(brown) and I was told that they were able to live together in a fishtank.
The two fish immediatly searched for eachother and showed some signs of agressive behaviour (swimming towards eachother and making themselves appear larger etc.)
The next morning I saw that my new female ancistrus had severely damaged fins. All her fins seem to be ripped apart. She does still seem healthy but she does appear to be stressed.
I seperated them, not knowing what would be the best option.
I really hope my new fish will heal but I'm not sure what to do or why they show this behaviour. The male is showing this agressive behaviour.
My fish tank isn't very large but it does have some hiding spots (plant pots, plants, a statue and a piece of driftwood).
I hope somebody could tell me what options there are

(In the attachment you can find a picture of the tail of my fish. The wounds are worse than they look, though. Also, the backfin and other fins are badly injured, but I could't take a better picture, unfortunately)
Kind regards,
Femke