When will I see some fry?

[afremont]

I have some mosquitofish (gambusia affinis) that I caught in the back yard. I've had them in a tank for a few months. They were pretty small when I got them, but they have since grown up quite a bit. All of the females seem pregnant, but a couple look like they will pop. I have never seen any fry, but I'm sure that some have been born and then promptly eaten by the other tankmates. This one female looks like she will pop, but she's been pretty big for a while. Gestation is supposed to be 24 days, and I'm sure I've been watching her at least that long. The biggest one has blue areas visible from the back, the gravid spot is huge. These are not all the same individual, but you can see I have plenty of potential mommies.

Can they refuse to deliver if they don't like something about the conditions?

[mnemenoi]

Try adding some dense plants, they will offer the fry a spot to hide from the adults. They can stand some truly depravable water conditions and breed continuously. I bet its just a matter of time before you start seeing fry. You can add a bit of aquarium salt, not enough to transition to brackish, but just a few teaspoons and it might help. What size tank are they in and do you have the water parameters? They appreciate hard water 7.5+, basically what comes from our tap should be great. Try some floating foliage and frozen/live food and it might get the ball rolling.

[afremont]

Thanks for the reply, I have 10 fish now in a ten gallon tank, most seem to be females and pregnant. I have some salt in the tank (~1Tbsp/10 gallons). I originally had approx 14 fish, but a few somehow disappeared without trace. Sadly, I lost the cycle on the tank after using maracyn to remove a cyanobacteria outbreak, and they got exposed to some ammonia for a few days before I caught it. One smaller male didn't make it, seemed to get a little bit of pop-eye at the end so I suspected a secondary infection from the gill damage. I examined him under the microscope and the secondary lamillae (sp?) seemed to be completely eroded away. :( The fat female had me worried for a couple of days, but she seems to be doing well now and eating plenty. Everyone seems back to normal now that I have the water under control.

I've got a bunch of small plastic plants with fine "leaves" and a pile of mexican river stones that the fry should be able to hide in. I'll still try to find a live plant and put it in there. Maybe java moss?

Here is a pic of the setup:

[mnemenoi]

Java Moss is great for a bottom cover and nearly any floater with long roots will provide cover for any fry that seem set on hanging at the surface.

[afremont]

Yep, saw a few fish missing this morning at feeding time. Started doing a partial water change and found the fish. My big female was being stalked by a couple of small males. I could see something hanging out that didn't look like poop, and it was getting longer. The other fish seemed to really get excited then and were obviously trying to snatch the fry right out of the mother. I had just used my warm water and only had about a gallon left so I filled the cheapo 1 gallon five sided tank and was able to quickly net her and put her in. I threw in a couple of fake plants and now have several fry swimming around. The female is still interested in eating so I put some dried blood worms in the tank for her to stuff up on, hoping that the fry would last longer in the tank with her. The fry to do seem interested in being near the surface, but there is plenty of oxygen in the water since it has an airstone in it.

[R_sustaita]

good thing you got them on time.

[afremont]

First one I saw drop after I moved her just fell to the gravel lifeless and I thought oh, no. But then I kept watching her and I saw one come out and promptly start swimming to the surface, amazing. Since then I've seen a few more, but I'm trying to just leave her and them alone for now. I have no idea how many were lost in the other tank, but judging from the size of her I'd say several. They're actually bigger than I was expecting them to be, pretty neat.

[R_sustaita]

where are the pics?

[afremont]

I dumped the one-gallon into the 5 gallon tank I have and when I filled the one gallon back up just to rinse out the remaining gravel, there were two more fry that had been buried in the avalanche. I spread the gravel out on the tank bottom and they all immediately hid in it. Hope I didn't trap any under some gravel. I put a couple of fake plants in, but they seem to prefer hiding in the gravel. I have no idea how many there are, a few though. I think the mommy ate some of them after she was done, that's why I moved everybody. She's back in the main tank now.

Next time there won't be any gravel in the birthing tank. I didn't think because I was in a hurry to get her away from the baby eating stalkers.

[R_sustaita]

that is just gross lol.

[afremont]

The two in the avalanche were fine after getting some water. I feel bad because I didn't fill it up for a couple of minutes though, so they must have been freaking out laying in the rock pile with no water. Of course they were just also born today so it probably wasn't the most traumatic thing that has happened to them so far. At least they weren't a tear-off meal like they would have been. All of them hide except one, and that one stays out in the open all the time. I guess he's the Darwin Award winner for the family, maybe I should relocate him to the main tank for dinner. jk

[R_sustaita]

i have 25 endler fry, it took me like a week to find out lol.

[afremont]

I don't think I have anywhere near that many, but there are a few.

This would be Darwin:


This is one that hides in the plant: