Male Swordtail - Aggressive Behaviour Towards Females

[tkdc80]

Hi all!
I am brand new to this forum, and to tropical fish. I am in the process of cycling my new tank (25G). I have done some research, and am following a 'stocking scheme' suggested in a book.
After stabilizing the tank and it's temp for a few days (about 25 celsius), I added 3 red velvet swordtails (1 male, 2 female). When I picked out the fish at the store, there were 3 males in the velvet tank - and I noticed 2 larger ones would pick on one smaller on as soon as he came near. I chose one of the larger males, assuming that the smaller one was 'weak'.
Well, I have had my fish at home now for 3 days - and the male started intermittently harassing the females on the second day. Today (3rd day) he is incessantly bothering one or the other of the females. He nips at them (fins, body, even mouth if he meets them face to face!), and stalks them. At times he gets super aggressive, curving his body and shaking his tail, then charging at them. He picks on one female more than the other (she seems to be the meeker one). I haven't seen any visible nips/tears on the female's bodies yet, but the poor ladies don't get a minutes rest, especially the one. I am worried that this will stress them out. I have seen suggestions to add another female - but i am wary about adding a fourth fish to my cycling tank.
Is he just overly amourous? Does this have something to do with the cycling (my ammonia levels are still 0)? Or did I simply choose an aggressive fish, and he will remain this way?
I appreciate your answers/suggestions, and would be happy to answer any questions

Tamara

 

[LauraFrog]

Bump. I think this needs a proper answer.

For what it's worth, I have seen something similar happening. I have a very small tank, about the smallest that I would try to keep mollies in. I brought home two females, but one of the 'females' was a juvenile male. It became very obvious that a gonopodium was developing and he began to harass the female. I couldn't add another female in the tank I had, so I had to give away the male. The reason people recommend putting in extra females is because if the male is just lovestruck and is harassing the females to mate, he will spread his advances over all the females, so the more females there are, the less any one gets bothered and they aren't as stressed. If the male is picking on one female constantly, adding more females might not work.

Anybody else got some advice? That's incomplete.

 

[tkdc80]

Thanks for the input. That's what I was worried about - that his picking on the one female would not necessarily be helped by adding another. Since my original post, I have purchased a divider and have him in "solitary confinement" I'm just not sure how long to keep him there!
The females behave so differently now; one was beginning to continuously swim up and down the glass (vertically), and she has already stopped this. I think I may keep him separated until I am done cycling, and then release him before adding any more fish, to see if he's "learned his lesson", haha. If not...he may have to be relocated. I hope not - he's a beauty

 

[LauraFrog]

All of my platies occasionally do the 'swimming up and down the glass' thing and there's nothing wrong with them. I think they see their reflections in the glass and chase it until they get bored. Fish aren't smart enough to work out that they are seeing a reflection and not another fish.

 

[tkdc80]

Thanks, LauraFrog - good to know that's normal.
I'm starting to think I just chose a really feisty bunch of fish. Now that my male is separated, one of the females (the one that was getting picked on by the male before!) has started nipping at the other.

 

[LauraFrog]

I think they're a bit like chickens. If you have a really aggressive chook pecking the feathers off the others and you roast it, the next most aggressive will peck the feathers off the others instead. I'm lucky that mine don't fight - the mollies try to steal the plec's food and the plec bites them, but other than that my tank is really peaceful, except when they decide to eat the fry and then they fight over who gets to eat the fry and all the fry escape. haha.
Adding more fish will probably help because if you have some aggressive dominant types, they will chase whoever is nearest them and leave the others alone. Once the tank is cycled I would get more fish. The tank is enormous, you should have no problem adding more.