# Aggressive Mollies? Yep, sure enough



## ReStart (Jan 3, 2011)

A couple of weeks ago, my wife saw some Dalmatian Mollies and really liked them. I thought they were ok and if she wants a particular fish, I'm old enough and smart enough to buy that fish.

So we bought 1 male and 2 females. This was from one of the best LFS in Memphis. I put them in the 10g community tank and took out three Zebra Danios to balance the bio load. The Zebras went into my newly cycled 60G tall which had a half dozen juvenile Rainbows, a few Golden Barbs, etc.

Almost immediately the male Dalmatian Mollie starting banging into the female Lyertail Mollie and chasing her endlessly. By far, the most aggressive fish in the tank. Then he started on the Mickey Mouse Platies, both male and female. He even took a run at my Dwarf Flame Gourami. The poor Neons just hid.

All right now, I've had enough of this. I put him in the 60G thinking he would be over his head there. Sure enough he stopped chasing. Guess what happened next?

The darn female Dalmatians picked up where he left off! They started chasing and banging any fish in the 10g whenever they got close enough. Gee Whiz. I've never had Mollies be a problem in a community tank. 

Tonight, I got tired of this and put them in the 60G with the male. So far, so good. They are pretty much just chasing each other. The Rainbows, even as juveniles, are bigger and faster than the Dalmatians. They also seem disinclined to take any crap from the Dalmatians. I don't know what I'll do if the Dalmatians start up their stuff in the 60. I'm not going to have a Dalmatian only tank. I already have 4 tanks in the den. MTS for sure.


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## phys (Feb 4, 2011)

give it time and some fish will stop being so aggressive once their territory is established. You could return one or two also...


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## webgeek (Feb 15, 2011)

I have this problem and all i do is to keep them in separate tanks. I separated 3 troublesome mollies into three different tanks and have put some baby mollies to give company. I've noticed that the chasing had quite a toll on their health. Possibly injuries. This is evident that they aren't growing much and their shape isn't like a well grown mollly.


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## snail (Aug 6, 2010)

10 gallon sounds kind of small for the mollies plus several other fish. It doesn't give them a chance to have their own space. Breaking up the space with plants and decor can help. Make sure you are not overstocked.


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## ReStart (Jan 3, 2011)

Y'all are right. When they went into the 60g all the chasing stopped. The 10g is overstocked but I thought since the chemistry was perfect, no problem. Wrong. Overstocking causes behavior problems as well as water quality problems.

I just this weekend set up another 10g underneath the first one and am doing a fishless cycle on it now. I was going to use it as a hospital/isolation tank but now am thinking to split the fish load between them and buy another 10g for the hospital tank. MTS. And on top of that, I keep seeing 55g's on Craigslist for like 75 bucks. Dang.

Mollies are pretty big fish when healthy. My Rainbows are growing so fast that I thought I had lost one. Duh, he had grown so much that I did not recognize him! And believe me, I LOOK every day. Flake plus frozen brine shrimp and bloodworms and WOW!


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## jrman83 (Jul 9, 2010)

ReStart said:


> Y'all are right. When they went into the 60g all the chasing stopped. The 10g is overstocked but I thought since the chemistry was perfect, no problem. Wrong. Overstocking causes behavior problems as well as water quality problems.


This is something that is hard to get people new to the hobby to realize. It is good that you're actually seeing the difference. Overstocking doesn't always mean that you have ammonia, nitrite, or nitrate issues. Stress can be created by trying to add and add until you've reached the physical limit, all the while exceeding the limit the fish can handle. Stress is what causes the fish's natural immunity to break down against disease, which is present in every tank. Not speaking of your situation, just in general.


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## snail (Aug 6, 2010)

Glad it worked out. Sometimes even things that should work by the books don't because every fish has it's own personality, part of what makes the hobby interesting.


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