Just How Aggressive Are Sailfin Mollies?

[Weaver]

Ive had to do a lot of rehousing lately due to my sailfin mollies which I recently bought.Ive firstly had to seperate the two males and then had to move opalines because the male sailfin was being bullied by it
I thought I had it sorted but now the male sailfin is beating up on the two dwarf gourami
Are they all like this or have I just got a particularly nasty one?
Cant even give the brute back as I bought him 40 odd miles away
Luckily tank number 6 is coming this weekend-another 4ft so I should be able to have a few more options.

 

[rrey82]

Don't worry mollies are like that especially sailfins. They are territorial especially if put with other male sailfin mollies....really matters on the fish too. I have multiple colorations of balloon, sailfin, and just basic mollies which I breed. Male sailfin mollies do best if there are only female mollies and in one seperate tank. All mine are seperated by aquarium dividers that gives me the chance to seperate all my kinds of mollies so there will be no interbreeding. Mollies do have minds of their own. Some of my female mollies don't like each other so they chase each other around, but nothing bad has happened to them. Have fun with your sailfin mollies.

 

[chrisquinn12]

I found my sailfins to be agressive when they were in too small a tank. In the big tank they all seem much happier.

 

[smithy05]

the mollies in me dads tank all stay at very top tank constantly, is this normal? see em in LFS and thy swim all over even if just few in there, he has bout 15 couple males but majority females, also with sexing not sure if these are babies or if males stay small but females are huge compared to males even when not preggas

 

[Annastasia]

What size tank are they all in, any other fish, and what are your ammonia, nitrite, and nitrate stats? Do the fish appear to be gasping? Do you have an airstone?

Any more information you can give us about the tank would be good. It sounds to me like something is wrong, I know my Mollies are all over the tank. As for sexing...yes, males tend to be a bit smaller then females. Depending on the species. The easiest way to tell is the anal fin. That's the one near their tail, under their stomach. A females will be rounded, like a fan, and a male's will be pointed.


Weaver - I felt bad about hi-jacking, so I'll add my thoughts on your post. Yes, Sailfins tend to be more aggressive then other Mollies, especially with the males. I've always had to keep at least 3 females per male, otherwise they get very territorial and aggressive. Usually it's best to have only one male per tank, as rrey said, but it also depends on tank size. Hope you get things figured out!

 

[smithy05]

not sure of water stats me dad cant find the kit for it (think me mom tidied up) but they dont appear gasping and have bred but they eat tons,
and recently we got 2 babies.
i think he a rekord i going LFS fri cos upgrading me own tank will post wot sort than post stats to

the tanks bout 3ft L by 1 1/2 W and 1 1/2-2ft high

the other fish are these

2 paradise (m+f)
1 female siamese fighter
few guppies
2 clown loach and thats it
8 neons
4/5 mollies
and 5 i think barbs/tetra there orange with a black stripe bout where the gills are and a black top fin (fish biology not good sorry) lol

the paradise, neons and orange tetras swim near bottom/middle. as does the siamese but that likes swiming amongst the plants and wood

we got 3 plants in it to along with bit bogwood and he used peashingle for gravel (thoroughly washed and rinsed) no airstone but big filter

the paradise n siamese are new editions but the mollies have been like this for ages and he used the dechlorinate stuff first and it was left bout 2days b4 he added any fish at all. could a big water change help??? oh and when i had 3 in my tank they swam everywhere. and they were with widows & danios. bit long i know but hope this helps

 

[Annastasia]

Okay, so you have yourself about a 50 gallon.

How often do you do water changes? A big water change could help, but not too big. Maybe about 50%. I'm thinking the levels may be up, and that may make them gasp. Or not enough oxygen in the tank. Do you have an airstone? Do all of the Mollies hang out at the top?

 

[tonymaloney]

I've not had any problems with mollies being agressive to one another. Sure they chase each other around now and again but I think that's natural.

Regarding the sexing, aside from the anal fin being a clue to sex, a vet friend of mine told me that mollies can change sex - anyone else heard this??

 

[Weaver]

Thanks for the replies
The sailfin has now been transferred to a smaller 3 ft tank where he seems happy as larry and is not bothering the 2 pearl gourami which are in it.
The only thing I cant understand is that all the lfs locally insist on selling sailfins in pairs whereas the good folks on here are saying that the ratio is 1 male to 2/3 females.Ive got 2 ordinary female mollies to keep him company and left the 2 bigger sailfin females in the 55g(uk) with the other male.
btw-- I wouldnt keep anything as big as a sailfin molly in a small tank and this molly is the biggest molly Ive seen since Molly McKee who I used to go to school with

 

[chrisquinn12]

The only thing I cant understand is that all the lfs locally insist on selling sailfins in pairs whereas the good folks on here are saying that the ratio is 1 male to 2/3 females.

The same problem when I first bought mine. Thats why I have 3 pairs...They say this is how they buy them so this is how they have to sell them...And being absolutly new at it then I took their advice...

But I have since found stores that sell them how ever you want.

Even so now I have a bigger tank I have no problem with 3 males and 3 females...

 

[tonilee7]

I think sail fin molly's are agressive, I had 5 in a big 4 foot tank with about 20 females and they kept killing each other till there was one left and it was the biggest one in there. I think they were just working out their pecking order. I bought 3 new ones and sure enough they got killed with in a week so I got rid of a few of my females and I got a new tank then put the agressive male in the new smaller tank with a few females of his own, and now I have no problems. And I didn't buy any more sail fins I got normal and balloon mollies and I have had no trouble so far. (touch wood)