9 replies to this topic

[Sean Phillips]

I've had this trio of affinis for months now and until a few days ago was keeping them in a 20 high with some Johnny darters and never found ONE fry, from gambusia! So I and a few others I told began to think either the fry were being eaten, or the parents were scared to breed around predators. So, I put the three in a plastic pentagon 2 gallon tank with half of it being tangles of a large spawning mop and the other side being pretty heavily planted with hornwort I rooted into the substrate. Two days later (today) and I find about 9-10 fry laying on the bottom! So I guess it must've been the parents scared to drop fry until now. Anyway, when I saw the fry I noticed that they were still absorbing their egg sac but also many were laying motionless either upright or in the case of many of them, on their side. I transferred as many of them I could find which was like I said, 9-10 of them, into my only available "transparent water holding apparatus", so in other words, a 0.50-0.75 gallon breeder box. I don't have the box attached to a tank so right now I just have it sitting full of water next to the adults' tank. Based on what I know about gambusia, can I assume that they will be ok without aeration as long as I change a bit of the water daily, or do fry need more DO than adults as there's currently no aeration in this fry "tank". Also, is it normal for them to be laying on their sides as they are?

The Breeding Setups:


Fry Tank:


Fry:


Fry:

[Sean Phillips]

Just found another 12-14 fry in the parents' tank, I'll put them with the rest of the fry later. No aeration suggestions!

[Matt DeLaVega]

I would lightly bubble it. They cant sip air from the surface like mom yet.

[Sean Phillips]

Will do, I decided to add a very small amount of flow to it before I left. It's only a trickle of bubbles but I'm running a 15, a 10, a 2, and a 0.5 all on the same air pump rated for up to 30 gallons so I think I'm getting my use out of it .

[gerald]

Looks like they were born premature, possibly due to moving the mother (just a guess).  They normally swim very well immediately after birth.  The "preemies" might continue to develop normally, or they might remain "belly-sliders" with under-developed swim bladders, as often happens with killifish hatched too early or too late.

[Sean Phillips]

Looks like they were born premature, possibly due to moving the mother (just a guess).  They normally swim very well immediately after birth.  The "preemies" might continue to develop normally, or they might remain "belly-sliders" with under-developed swim bladders, as often happens with killifish hatched too early or too late.

Oh. Should I wait until they absorb their egg sac to try to feed them for the ones that survive.

[gzeiger]

Yes.

[Sean Phillips]

Had about 5 die so far, 22 left. Hopefully I can get at least six to survive for BAP for my local fish club.

[gzeiger]

This is really interesting. Gambusia fry are normally quite independent immediately.

[smbass]

I think moving them triggered the spawn as someone else suggested. This is a common occurrence with livebearers. I sell and ship H. formosa frequently and it is not uncommon for me to ship females and the customer tell me there are extra fish when they arrive. It seems just a little stress and the female will drop the young early. It will be interesting to see if these continue to develop and survive despite coming out early.