Sailfin Mollies

[omen666]

I have one pair of Sailfin mollies. They have had 2 lots of babies and I did not know she was even pregnant until I found them in the tank. The mollies swim around all of my guppy babies and most of my guppies don't eat their young so I just leave them...but the babies disappeared and the other day! I noticed that the Guppies know that these babies are different, and they chase them down and eat them I wanted to thump her for it so I have removed the babies. IS this common? I've never seen a guppy that could distinguish the difference in young fry. She leaves the guppy babies alone and in peace. The cow!

 

[nmonks]

It is, sadly, quite common for most livebearers to eat baby fish, even their own, if given the chance. Livebearers don't form pairs and they extend any kind of broodcare to their offspring. In the wild, baby livebearers tend to live in very shallow, thickly planted water where their parents don't go. Hence, evolution doesn't need to "hard wire" any kind of behaviour to prevent the parents eating the babies, because the parents would rarely encounter the babies. In an aquarium, we create an artificial situation where parents and offspring live together, and the result is that the parent views the baby just as it would any other tiny animal: as food.

You can improve things a bit by installing floating plants, stuff like hornwort, Indian watersprite, or even Java fern leaves. Baby fish hide among them, largely out of the view of the parents, and will be safe for at least a few days until you can transport them to another aquarium.

Cheers,

Neale

 

[omen666]

Thanks Neale

But does this behaviour prove that she knows those babies are different? She just had about 50 babies of her own and has not bothered them, she swims right beside those babies but if one of the mollies comes near she goes for it. It's almost as if she is protecting her babies, and I have never seen a guppy do this.

I know of a man who shows guppies and if he has a female who eats her young he gives her a 2nd chance and if she repeats this behaviour he destroys them. I could never do that but would it suggest that this is passed on?

All fry are similar in age but she knows the difference in them...

 

[nmonks]

Now then, your two points here are both interesting and apply to different things.

It's hard to imagine a female molly "recognises" her young in any meaningful way and there's no evidence they have any maternal behaviour. Evolution certainly wouldn't have given them any, given that in the wild the babies and the mothers inhabit different parts of the stream or pond. Instead of broodcare, livebearers invest in producing the biggest possible babies that are able to swim straight to the safest places in the the stream and pond and to swim away from potential predators.

So while I'd never say never, it's highly unlikely she is "caring" for them. She may be ignoring them, or entertained by them, or simply curious about them. But, as yet, she apparently doesn't view them as food.

Now, there is some variation in how predatory livebearers are. Some people have specimens that ignore their fry (my halfbeaks, so far, have been very good) but other people have exactly the same species and found the mothers ate the babies straight away. So there is some background variation there. Perhaps genetic, perhaps diet, perhaps other factors.

Your guppy-breeding friend is apparently trying to shift the genes in his stock towards mothers that ignore the babies. Obviously, this makes his life easier by meaning he doesn't need to rush to separate the babies from the parents. Whether this breeding-in of this particular "good behaviour" works or not, I do not know. It is certainly worth trying.

Cheers,

Neale

 

[omen666]

It's not the Mollie who is protecting , she could care less , she just dropped them off and that was it! It's the female guppy who is fending off the mollie babies. She spots a mollie baby and thats it...*Gulp* However, she leaves her own babies alone.

 

[nmonks]

Even odder! I have no idea what's going on then. As I said, some mothers ignore babies of their species, while others eat them, so maybe you have a guppy that ignores baby guppies but eats baby mollies? This certainly isn't normal, as often guppies are quite cannibalistic, but maybe you've lucked out and got one that isn't!

Neale

It's not the Mollie who is protecting , she could care less , she just dropped them off and that was it! It's the female guppy who is fending off the mollie babies. She spots a mollie baby and thats it...*Gulp* However, she leaves her own babies alone.

 

[lilfishie]

i have known mollies to eat other fry and never there own but never heard of it in any other livebearer

 

[wei0204]

From my experience, I think Molly is tamer compared to Guppy as they(Molly) can get along well with their fry. Guppy normally eats its fry or others' fry.

 

[dwarfgourami]

From my experience, I think Molly is tamer compared to Guppy as they(Molly) can get along well with their fry. Guppy normally eats its fry or others' fry.

I think it's all down to individual personality: I've had guppies that deliberately hunted fry, and others that didn't touch them if they swam right past their noses.