Aggressive Female Sailfin Molly

Hi again everyone. Hopefully a quick question.

I have 5 mollies in my 60l tank. I now know that they will outgrow this tank so I'll either get a much bigger tank (hopefully)  😉 or they'll be moved on as they grow.

One of the females is a right bully! She harassing anything that moves at the moment. Even the larger male! I THINK I have 1 male 4 females but there could be an immature male in disguise!

I was thinking that she could be pregnant but now I've looked it up she doesn't have the dark gravid spot although she does look quite bloated. Is it compulsory to have the spot?

Water parameters are as good as I can get em. I'm even using 50/50 ro/tap water to make things a little more cosy. (I have high ph and nitrates in my tap water).

Many thanks for reading.

It is hard to tell from the photo I'm afraid.

Late maturing males will look like females, so the fan shaped anal fin isn't definitely 100% female until you know the fish is mature.
Not all females get a gravid spot when pregnant, it depends of the muscle development and skin/scale pigmentation around that area. Thick muscles and heavy pigmentation obscure the gravid spot, and larger fish will have more muscles.

Females which are near to dropping fry tend to become more aggressive; they prefer to be left alone and will object to being disturbed. In the last few days, their body shape looks as though they have swallowed a box, although a young female won't get quite this bad as they have smaller numbers of fry for the first few batches.

Just because mollies are normally not aggressive doesn't mean they all conform to the norm. There is always the change of a rogue fish in any species.

If this one is proving to be a problem, rehoming her might well the best option for the other fish.

What is your water hardness?  Mollies like hard water and if you are using 50 50 RO and tap water this will decrease the hardness.

Hi guys.

My water out of my tap is liquid Rock! 😂
The 50/50 mix is giving me around 6° GH and 8° KH which according to API is fine for mollies. I wanted to broaden my scope of fish I could keep so brought the hardness and PH down to a more accommodating level.

I've taken the aggressive little get back to the shop. When I got home I have some fry!! Now not sure if it was her or maybe another that dropped them while the bully was segregated for the night.

Oh,,,,,,,,,,,,

OK Im pretty sure you're right Sue. They are displaying signs of the 'shimmies' so just checked my GH and KH again. 7° and 5° respectively. So here goes. Going to do a 10l water change using 75% tap and 25%  RO. Hopefully that will begin to raise my hardness a tad again for them. I suppose once settled I'll just have to find the right balance

At the moment is just a pair of Dwarf gourami with them and this site says they should be fine with the water a little harder.

This hobby is taxing. 😰