strange looking cuttlefish hatchling

Do they normally hatch with a yolk sac, or should this not be fully absorbed by the time they break free of the egg capsule? Sounds premature.

Two mutations in one clutch of eggs? That's odd! UV light source on these eggs (or nuclear power plant in the vicinity) by any chance?

Normal light/dark cycle in the tank? Any spikes in water temperature?

Have you a source of appropriate-sized live food?
 
Good Evening from Germany :cyclops:

Here comes a picture of our second mutant-baby. I took it yesterday. I know it is not very clear, but I didn't want to stress the little guy too much.
binobabybranched2yolk.jpg

The white arrow indicated the cleaved armtip (dorsal view). The baby was still alive today (2nd postembryonic day) - also still carrying its yolk sac. The yolk sac is shrunken though...

I had a look through v. Boletzky, Lemaire, Fioroni and others (basically all sepia-embryology articles I could get :shock: ) to find out if the presence of an outer yolk sac in S. officinalis means premature hatching. I am still not sure. I have seen many hatchlings with small outer yolk sacs in our groups, so I didn't regard it as uncommon... until now.
What do you experts say about this? :? Some of our other babies discarded the yolk sac after some time. Are they always fully absorbed (not discarded) normally???

The eggs are kept under experimental conditions (i. e. constant temp, O2 and CO2). They have normal light-dark conditions (sunlight [not directly exposed to sunlight though]) and are not illuminated with any special light...
The "clutch" consists of eggs from more than one female. So our two branched-arm-babies may not really come from a single clutch...
Yes, we have a good living food resource for the babies. They are fed on Mysis (selfcaught or bought) until they grow older...

TK :cuttle:
 
Sounds like you've got things under control then (environment and food).

If one of our Sepioteuthis squid hatched with a yolk sac of that size it would, without a doubt, die (a dead give away that someone had handled or disturbed the egg mass, suddenly increased the illumination, or otherwise disturbed the eggs). I don't know about cuttles though .... it doesn't seem right to me that this one has hatched without fully absorbing the yolk; that it is still alive, and that the yolk sac is obviously decreasing in size, is good. I wouldn't remove that beast from the tank, or otherwise disturb it (even for a pic) until the yolk has fully gone (if the sac 'breaks off' when the animal is disturbed, you can assure yourself that it will be dead by days end).

I'd be inclined to remove any protein skimmer for at least (the very least) the first 10 days. I hope I'm not putting you wrong here; perhaps if you have others in tanks then you could trial these without a skimmer. I do believe that the paralarvae absorb DOM through the skin, so removing it removes a vital food source.
 
I have a lot of Raja spp. hatch with Yolk sacks still on and have seen a few cuttles with it, but have such a larg number of them that I can't be sure which die off in the first few days.

I only feed on dead food though and obviously they aren't hunting so i'd say that they would grow slower and therefore be picked off by the larger, more agressive hatchlings in the tank. I'll separate the next one I get and see!

~Andy
 

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