Newbie with a Molly Fry Question

[SSS]

Hello,

Almost 3 months ago my female sunset molly gave birth. It was a small batch and only 4 survived. The female mother died a couple weeks after birth for reasons unknown...I think the male stressed her.

After 2 weeks I re-introduced the fry into the main tank. Things have been going quite well since then, the fry have tripled in size and are very active. Recently I noticed 2 of the fry were picking on thier father. They nipped at him to the point where he got sick. I removed the father from the tank and put him in a safe zone. I then changed 20% of the water in the tank and added a little pinch of salt to the tank. After a couple days the male was back in good shape. I released him back into the main tank. Within a couple of minutes the same 2 fry began nipping at him again. They chased him all over the tank. I was appalled.

The only solution I could come up with is remove the 2 offending fry and place them in a breeder tank hangning off the side of the main tank. I kept them in there for a couple of days during which time the male father molly was looking very healthy again. I thought I would try releasing the incarcerated fry back into the main tank. Once again within minutes they were attacking the male father. Now the other 2 fry of the 4 have been very well behaved, they don't bother anyone in the tank. I don't understand why the other 2 are so aggressive. I have jailed them back up in the breeder tank but they can't stay there forever. What is going on here? Should I remove the 2 offending fry permanently? Why is the father the first and only target they go after? Could it be tank conditions or feeding conditions that are causing this?

Any help would be appreciated. Thanks!

 

[SSS]

The father is a Sailfin Sunset Molly, I dont think that makes a difference but I thought I would share it. He wont stand up for himself either. The 2 offending fry are not just nipping fins, they are nipping at every part of their father. I don't like this behavior in my tank. Things were fine until about 5 days ago when this began.

 

[krap101]

i guess more active is better .

ive had an incedent with that. one female guppy attacked another. died the next day. are you planning on keeping the babies or like selling them? because if you were gonna sell em you could keep em in the breeding net until they get to a decent size. or get a tank divider. or get a new tank

 

[SSS]

I would love to keep them if I can but not if these 2 are gonna bother my other fish.

 

[newaridiar]

Are the two males? That could be what is making them so aggressive, more males than females in the tank. I've never seen anything like that with my mollies, but I usually take the fry to the LFS as soon as the owner will take them (about 1-1.5")

Pity your female died, my female had a very small first group of fry as well, but after that she started having more at a time

 

[SSS]

They are still too young to tell what sex they are. I sperated them into my spare 10 gallon tank today after the final attempt at releasing them back into the main tank. Once again they went after the male. I quickly netted them and transferred them over. The 2 offending fry are fine together seperated from the rest of the bunch. Right now they are floating around together. It's just when they see my sailfin that they go after him. Do mollies go thgough a "teething" stage as they begin to mature?

 

[newaridiar]

I don't think so, and IMO things will probably get worse between these two and the male as they get bigger and closer to his size. If they are already attacking him while they are too small for you to sex, then I can;t see them getting any better when they get full size

 

[SSS]

I came home and found the male molly laying on his side in the back of the tank with all 4 babies picking at him. He was motionless but alive. I removed him from the tank and he is in pretty bad shape. I think the fry were picking on him all day and he finally gave in. He has crashed on the bottom of the other tank and seems to be floating belly-up even though he is still fighting to remain upright.

He seems to be out numbered by his pint size off-spring. I don't think he is gonna make it. He has bounced back on several occasions already. He has been very hearty in the past but I don't know what to do. I can't afford to set up the other aquarium full time or upgrade to a bigger one at the current moment.

I cleaned the tank really good today, I cleaned the rocks and filter system. It was dirty in there. I plan to do another cleaning on Friday because I didn't want to change out more than 20% of the water in one day. I don't know if it will help, it won't hurt. I can't keep the male in the breeder/separator for longer than a couple days. I will be forced to release him back and let nature run its course. He won't even defend himself, he won't try to bat the fry off of him anymore. I found him just laying on the bottom looking dead for the most part. There are some wounds on him from the fry. I didn't see this yesterday but there is a minor red sore on his side today. I don't see anything else that would make me think he is sick but then again, he could be sick or dying for reasons other than the fry.