Male Platy Bully

[Jenn.B]

So I have 4 platies, 2 males and 2 females (yes I know I should have more females). I've had them in my tank the longest, they've had no problems, until now, recently one pair (1 male and 1 female) got bigger than the other pair, one male in particular is a lot bigger than the other. The bigger one is constantly chasing the smaller one until the small one hides in the corner under some willow moss. Is there a way to fix this, I hate to see the small one chased all over the tank. Should I get more females? The other option I can think of is to move the small one to my 10g fry tank, which is currently housing about 30 molly fry, but would he eat the fry? (they're maybe a half inch long) Any help or advice would be welcome, I'm at a loss...

 

[MdngtRain]

You can either move him, or get 4 more females. Moving him might be easier, I have not yet witnessed my platys eating their fry, but I am sure it happens. I doubt he would eat all of them tho... The risk is up to you. So far, I have had similar experiences with all types of live-bearers, and the only respite the bullied ones got was when they and the bully were separated... You may lose some fry, but you will likely lose some anyhow. I hadn't had a full batch survive yet, even when not exposed to parents or other predatory fish...

 

[Jenn.B]

Ok thanks, I think I'll move him with the fry and observe him for the night, and if I catch him munching or harassing the fry, move him back to the main tank. I'll also see about getting more females.
Any ideas as to why he's so small?? His body mass is probably only about half of the other male, and I thought they were the same age. Would separating him and making sure he gets food let him get bigger?

 

[Thyra]

I think with all the inbreeding that probably goes on that a lot of fish will never grow to their full potential. Out of the fry that survived (mollies) I had two that, although apparently healthy and eating with the rest never grew to much more than an inch, even after almost a year and they both eventually just died. They were from different mothers in separate tanks.

 

[Jenn.B]

Well he's in the fry tank and is being respectful of the fry...he approaches them and they dart off, but he doesn't chase them I think I'll leave him in there awhile and see if he grows. The fry tank is going to go to my sister anyways and become her fish tank, so if he stays small enough that he would still be chased, she will get to keep him.

 

[MdngtRain]

Jen, I'm glad he is doing better in the fry tank. I hope it keeps up.

 

[Jenn.B]

Thanks, I hope so too!
I also added a young dwarf synodontis to the fry tank to help clean up, and he seems to be getting along with all the other tank inhabitants well too, plus he looks really awesome *BOUNCINGS

 

[Jenn.B]

Ok so the male in the fry tank is thriving, much to my relief. He isn't however, growing to match the size of the others, but seeing as he's happy in there I think he's become a permanent inhabitant.
I have an new problem now with the bully in the main tank. I'm almost positive both females in the 28g with him are pregnant. The male keeps chasing them until they hide somewhere he didn't see (he especially goes after the yellow one). I don't want him to stress them out to the point that they terminate their pregnancies or even die, so I put him in my breeder's net for now. However I don't want to stress him out either. What should I do? Should I shuffle all the platies up and put a different combination in the fry tank? (the fry are big enough that they can't be eaten). And is the color of the platies making one more of a target than the other? The mean male is orange, along with one of the females (rainbow platies?) , while the other female and the bullied/moved male are yellow (pineapple platies).

 

[OrangeCones]

Ok so the male in the fry tank is thriving, much to my relief. He isn't however, growing to match the size of the others

All fish put of a hormone that will stunt those around them to make sure they have enough room for growth, food resources, etc. In a large tank with frequent water changes, you can dilute this hormone. With 30 fish in only a 10 gallon tank, the growth of most if not all will be stunted. A few may get good growth, but at the expense of others.

 

[Jenn.B]

The 30 in the tank are fry that are all well under an inch....and even when he was in the 28g (where he had plenty of room) he didn't grow as fast as the other 3.
Any suggestions as to what to do about the females being chased? I hate stressing out the male keeping him in the breeder's net.

 

[OrangeCones]

Jenn.B - unless the platies were born in your care, you'll likely have no idea what conditions they were kept in prior to you acquiring them. Fish that are captive bred in mass amounts are often inbred (especially when the breeders are 'developing' specific colors or body shapes), and may not be kept in ideal quantities given the volume of water. The stunting that happens early on in a fish's life due to the poor early conditions will not be reversed given good conditions later.

In my experience, live bearers do better in larger groups. When there are several males and twice or more as many females, no one fish is picked on or stressed out.

If your females are indeed pregnant, the lone male will chase them incessently to be nearby when the event happens. Live food will boost his strength and abilities (morbid though that sounds), so he will be drawn to them. Also, they mate constantly, so its not unusual for the behavior you are noticing.

More hiding places, rearranging the deco, and adding more platies in the proper ratio would be my suggestions if you want to keep them together in the same tank.

 

[Jenn.B]

Ok, the platies weren't born in my tank and I do plan on getting more once the molly fry in the fry tank grow big enough for some to be moved to the 28g (I want to know their sex first) and the rest my lfs said they'd be happy to take. I also plan on buying more live plants for both tanks once I get rid of the nuisance snails (I have clumps of willow moss in both tanks). In the meantime I let the male out of the breeder's net because he looked really stressed and I was going to move the females to the fry tank if he kept bothering them, however he seems to have "learned his lesson" and hasn't been chasing the females all over the tank.