Agressive Molly

[Britesprite]

I have a dalmation molly in my tank and she is turning into a big bully. She doesn't let my cories eat their sinking pellets and always chases the other fish in the tank around at feeding time. I am not worried about her hurting anyone but I do worry about the cories since they can't get any food, she chases them away and hogs the whole pellet to herself (what a pig!). She doesn't even go for the flake food on top, just goes straight to the bottom and starts looking for the sinking pellets when she knows it's feeding time. She is the biggest fish in the tank, do you think that maybe getting another molly that is the same size or bigger than her would help with the aggresive behavior? Or would it make it worse? I had my eye on this gorgeous green sailfin molly I saw at my LFS yesterday.
Her current tankmates are
-3 pearl danios
- 2 corey cats
- 1 oto cat
- some molly fry (in a breeding net as they are still really tiny)

 

[rdd1952]

Not certain what to tell you about the aggression but mollies are not good tankmates for cories or otos as mollies prefer brackish water with a much higher pH and KH than cories or otos.

 

[Britesprite]

Really? I have never heard that before. I have always kept my mollies this way and have never had a problem, they seem happy and healthy.

 

[rdd1952]

I'm not saying it won't work but that one of them will be out of their preferred water parameters. Mollies prefer alkaline water with a pH of 7 to 8 and a KH of 10+ while corys prefer acidic water with a pH of 7 or lower and KH of 10 or lower.

 

[Tokis-Phoenix]

Mollys can be kept in freshwater but it depends on the exact variety of molly and whether it was bred/born in freshwater and what the ph of the water where you live is like etc. My old gold and black female molly lived to just over 4years old, was born and raised in freshwater and kept in freshwater her entire life with no problems at all- Black mollys are an example of a variety of molly which tend to thrive better in brackish water.



The best thing i would advise to do is to feed the corys only after the lights in the tank have been turned off for the night, the corys will have no problem locating the food even in pitch black darkness.

I wouldn't advise getting any male mollys, it won't change the problem at all (any new mollys you add will also just copy her behaviour), and you really need at least 2-3females if you want a male, as male mollys have a high sex drive and will over-harrass the females if there aren't enough to go around.

How many gallons is your tank ?