Aggressive Dalmation Molly

[derby28]

Hi, Hope someone can help with this.

I've recently purchased two dalmation molly, one light and one dark. They basically look the same so I'm not sure on gender. When I purchased them from pets at home, I was given a damaged one which couldn't swim very well. I didn't notice this until it sunk to the bottom of my tank. A couple moments later the darker one started to chase the lighter one and must have stressed it out. Sadly it died. I thought it might have been picked on because it was already injured. My mum thought it would be nice to replace it with a nice and healthy one whilst I was at work, so when I arrived home I found another light one, again being tormented by the dark one. It didn't take long for it to suffer the same fate as the one before.

When I got the fish I wasn't told any specific advice so was just wondering what was going wrong. Are they meant to be kept in a larger group, or have I just got a bully in my tank? The remaining molly seems a very happy and active fish. I'm not sure whether to love it or hate it.

Any advice much appreciated, thanks

 

[Ava_Banana]

It sounds like the "agressive" on is a male.

You can tell this by seeing if it has the reproductive organ (Gonopodium http/en.mimi.hu/aquarium/gonopodium.html ).

Male mollies do tend to get quite "frisky"....and if a particularly "active" on is left with just one female, they may well chase it to death.

My advice is either to get more females (ratio of 1 male to three females) to spread his affections around, or to take the male back and get two females.

good luck.

 

[derby28]

This really doesn't make sense. Apparently both of the molly's were female though...

 

[frostyn]

I'd agree with Ava_Banana. It is important with mollies to make sure the females outnumber the males. You can tell them apart as the males are slightly smaller and slimmer and have the distinctive gonopodium. I'd be surprised if your aggressive molly was a female but if so, I'd take it back to the shop and try again with some new mollies. If you want to keep the one you have, I'd get another few females and if you can, separate the one you've got (either in a large net with some lead in the bottom or in a breeding hatchery or similar) to give the new ones some time to get used to their new surroundings (a day if you can). Sometimes, a few hours in solitary confinement is enough to calm an aggressive fish down too. If you only have mollies in the tank, you could add a little bit of aquarium salt to the water as mollies prefer this as it is closer to their natural habitat. Good luck!

 

[Ziggi]

I thought the easiest way to tell the male from female was to look at the dorsal fin, males (atleast my male) fins are bigger and flare up/down every now and again. also, females have two sets of fins on their abdomen, while males ... dont.

I could be wrong, but that my experience. and I agree, get 1-2 more females for him. but be prepared for lots-a babies!

 

[Rex740]

You dont really need 3 females, just 2. Ratio is 2 females to every 1 male. Make sure when you buy a new molly, you get the gender you want and tell the employee to get you that one. Always look for healthy fish to ask for, you shouldn't just say get me one of those fish, instead you should choose and ask for the one you want.

P.S.- Ziggi you are wrong. The way to see the gender is by looking near the bottom fins.

 

[derby28]

Thanks loads guys,
I'm going to try and get two more after work...
wish me luck