Fish aggression...need advice please

mishi8

Go fly a kite!
Jan 13, 2005
768
0
16
Alberta
I finally finished fishless cycling (yay! :clap: ) my 10 gallon, and added some new fish last Friday:
2 Gold Mickey Mouse Platies (1M, 1F)
2 Calico Platies (2F)
1 amano shrimp
1 zebra snail

The water tests well: 0 NH3, 0 NO2, 10 NO3, 7.6 pH, 78F And the fish adjusted well...all active and eating well. One of the calicos dropped fry yesterday (was a surprise to me!) and the other calico seems to have a gravid spot. After the fry were born (and promptly devoured! :eek: ), the male MM platy started "herding" the two calicos, and attacking the other female MM platy. It looks like this "female" MM is actually a young male who is still developing his gonopodium.

So, I need to take one of these males back and replace it with a female. Should I return the older, agressive one? Or the younger one? If I keep the older male, am I risking agressive behaviour when I introduce a new female? BTW, this older male also has a tail that is damaged (looks like a bite that is healing).

Thanks for your help!
mishi8
 
I'd return one of the males and get two females. I've heard male livebearers with only one mate will pick on them a lot. A second female will spread out the aggression.
 
mooman said:
I'd return one of the males and get two females. I've heard male livebearers with only one mate will pick on them a lot. A second female will spread out the aggression.

I've already got two females. The ratio I went for was 1M:3F, the salesperson made a mistake and netted a second male when it should have been female. I need to figure out which male should be returned in exchange for a female.
 
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mooman said:
I'd return one of the males and get two females. I've heard male livebearers with only one mate will pick on them a lot. A second female will spread out the aggression.
I may have this problem, should I risk over crowding the tank if it'll save my gold platy stress?
 
I would get the extra female. You can always make up for the increased bioload by doing a slightly larger water change.
 
greendeltatke said:
I don't think it matters much. If your current females seem stressed, maybe ditching the mature male would give them a break.

The females don't seemed stressed at all. The female with the gravid spot is keeping the others in line somewhat too (she'll probably drop fry in the next few days). At this point the agressive male and two females are swimming around together, and this male is chasing the younger male everytime he gets too close to the females. I've decided to return the younger male though. He wasn't eating as vigorously this morning. I think he may be getting attacked because he's weaker, or maybe even ill.
 
Update

Well, I did return the younger male and got a female MM platy instead. So now I have 1M MM Platy, 1F MM Platy and 2F Calico Platies. Unfortunately, the male is attacking this new female now. :( He's bit off parts of her pectoral fins. During feeding, she is active and able to easily get her fair share until most of the food is gone, then the male chases her away again. She's taken to hiding in a cave, or under plants some of the time...especially when the lights are on. I try to keep the lights off most of the time though, except during the early evening and during feedings.

So now what do I do? Should I return the male? Should I return this female and stick with only three fish for now? The fish were are getting along so well in the beginning...until the one female dropped her fry. :help:
 
That is one mean platy. :eek: I had a problem with one aggressive male and his two male tankmates (no females). I figured out that the agressive one was a swordtail hybrid, and probably not happy in my 20 gallon tank in the first place. I just took him out and peace descended in the tank.
 
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