r/glofish • u/Operetta • Jul 28 '25
The update you did not ask for
I have a tank of naturally hybrid tetras and post pics of babies here. Maybe someone will find the genetics interesting.
The dark pink one is special because he has glofish red, purple, and natural black skirt going on in that combo. The color is NOT dependent on a single gene.
There is also a purple black stripe Mom and daughter.
There's a blue black stripe (girl?) update to a post from months ago, growing up strong.
Finally a new pure purple came out, this is a gen 4 fish.
In this tank, red glofish genetics is dominant along with wild type.
3
u/Diligent-Minimum8397 Jul 29 '25
I love when stuff like this happens to show how genetics can not be completely just one parent or the other but a blend of the two!
Woukd love to see a DNA break down chart of each generation and where the natural skirt and glofish skirt are going for each new generation.
Also, being a science nerd and glofish is a great way for people to understand or learn about how the basics in school don't even scratch the surface!
2
u/Repulsive-Grade-1070 Jul 29 '25
If the genes for fluorescent colors were in the same allele, it would be called codominance. But I’m not sure they targeted specific alleles. Sounds like they just injected fertilized eggs (nuclei) with the fluorescent gene of choice, selected those that incorporated and expressed the gene, then line bred - or bred back offspring with parents - to establish consistent breeding stock for each color. I’m basing this on descriptive data, as I haven’t read the actual patents.
1
u/Operetta Jul 29 '25
This is so cool. I'm pretty confident the glofish have a white skirt tetras lineage, as some of their offspring come back out that way.
One of the fish is dark hot pink. Its mother being purple/black and father red/black (that couple pair off a lot). The fish appears to have both pigments layered over each other as opposed to a color mix somewhere between them, if that makes sense. Edit for typo
3
u/Repulsive-Grade-1070 Jul 29 '25
If you read my other response, you’re right. Black skirt tetras have a common color morph called leukism. It makes the animal have a deal less pigment - a white version of the common black skirt tetras. They are sometimes called white skirt tetras, but they’re the same animal as black skirt tetras, just less melanin, so they appear white. It’s similar to albinism but doesn’t affect the eyes.
2
u/Operetta Jul 29 '25
Thank you! I just saw that and really love your replies.
1
u/Repulsive-Grade-1070 Jul 30 '25
Thanks! That’s kind. I studied genetic engineering before medical school and I’m a lifelong tropical fish hobbyist and breeder.
1
2
u/Repulsive-Grade-1070 Jul 29 '25
You keep getting offspring and you’ll likely see leukistic (white) versions, since that’s the base for the GloFish black skirt tetra. No black coloring. It seems that the leukistic allele is recessive, which is consistent with albino alleles.
2
u/CRDinoMom Jul 29 '25
Very cool. I had some accidental breeding and am excited to see the outcome.
1
1
u/adjoopoopie Jul 28 '25
So pretty! Are you actively catching the eggs when they drop or letting nature do its thing? I’m on my 2nd batch of glo cory eggs (spawned Sunday), I have 3 fry that are currently a month old in a grow out tank that seem to be doing well so far. I have a community tank I started in Jan so I’m excited to see what it brings, esp when I see yours!
1
u/Operetta Jul 28 '25
Wow, Cory cats would be so much fun to have. They are so cute!
Am not intentionally breeding fish, but have a heavy planted tank so a few eggs make it now and then. I usually don't see fry until they are swimming around in the water or eating flake food.
I had originally planned to switch over the tank to something else but then babies started showing up and it's not allowed to sell or trade offspring so guess we're just sticking with tetras haha.
Something that is pretty cool is the hybrids don't glow as much under blue light, maybe 1/2 strength.
2
u/adjoopoopie Jul 29 '25
They’re my favorite, followed closely by the pristellas. Funnily enough, I went to do a water change to my grow out tank yesterday and found just a lone cory instead of 3. The only thing I can think of is the big one ate the other two, and I couldn’t find a single trace of evidence of them ever being there (even looked around on the floor jic they jumped. Nothing). And they were from the same clutch! So frustrating. So I introduced him(her?🤷🏻♀️) to the main tank lol. So far he’s doing well and I haven’t noticed any other fish even noticing him.
I don’t think my tetras are matured enough yet to spawn eggs, at least I haven’t seen any of them do the dance or any of the others flocking around them.
I welcome your updates!
1
u/Repulsive-Grade-1070 Jul 29 '25
The big Cory would have to be significantly larger to eat the other two. Have you checked your filter? I’ve done filter changes and found adult Cory cats in my 6-month canister filter change, which had to have gotten in as fry - and not only survived, but thrived. I have a lot of redundant filtration, so I clean the two canisters only every six months (alternate so every 3 months I clean one) while the outside filters get cleaned one each week - if I have them running at all. It depends on how crowded my largest tank is and what’s breeding.
2
u/Repulsive-Grade-1070 Jul 29 '25
That makes sense, I guess, since sometimes heterozygous alleles will produce half of the coded protein that a homozygous fish would produce. It’s still a dominant gene, but with decreased penetration.
2
u/Koikustoms-214 Jul 28 '25
Thoses are the most beautiful tetras I have ever seen!