Fish Twins

[keithp]

Is it possible for fish (both livebearing and egg laying) to produce an egg with two fish embryos inside of it? If it is possible, would the fish look identical, or if the species has color variations (like guppies,bettas) could the twin fish look different?

 

[Kizz]

I Do know it is possibly for 2 fry to come from 1 egg the first time my guppies gave birth i have conjoined fish . Dead fry's Stomach was attached to Live Fry's back . Unfortunatly it never survived. I suppose with your question it could work just like human twins you can get identical or non identical twins ...Anything's Possible

 

[keithp]

In your case they were fused together, could it happen where they are not fused after hatching? In other words there were 2 yolk sacs in the egg.

 

[Boony]

I'd have thought that it would be perfectly possible for one egg to contain two seperated embryos. During Mitosis (Or meiosis, can't remember) the single cell created from Sperm and Egg will start to divide, if this division results in the cell completely splitting off, then both cells will begin to divide as if they are seperate lives. This will result in the identical twin form. All the eggs that are laid and fertilised separatly can be considered non identical twins, the same for livebearers. Thats because non identical twins come from 2 separate eggs and 2 separate sperm, just happen to be growing at the same time.
Although in Live bearers you may not know that they are identical as they will have multiple babies, looking very similar. However, as for your question about the colour morphs, If they are identical (ie from the same egg/sperm mixture) they they will look the same, with only minor differences, the odd patch somewhere, as they both share the exact same DNA/Chromosomal pattern.
hope that answers your question.

 

[Jonathangerous]

The fact that an above poster obtained a conjoined twin indicates that it is possible to have monozygotic "twinning" in fish--I don't see why this wouldn't be applicable for egg layers, as well. Dizygotic twins are pretty much a fact of life for fish--I don't know of many species that bear but one offspring per gestation (using the term loosely).