[Kink at penduncle of guppy fry]

Thanks everyone, I had a feeling about it, but wanted to make sure I was doing the right thing. Appreciate the straight forward feedback.

[Kink at penduncle of guppy fry]

Hi new to having guppy fry.  I got some new females last month and the first round of fry are about a few weeks old.  I noticed about 8 fry have a bend or it kinks slightly at the peduncle (hoping I named the part properly, it's just before the tail starts).  The backs are straight and there's no problem with mobility. None of the adults (2 males, 6 females) display this.

What could cause this?  Genetic? Tank parameters?  (Ammonium Nitrite Nitrate safe, GH 11, KH 2, pH 7.8)

What should I do with kinked tail ones?  Will they outgrow this? Cull them?  Start an outdoor tub (never done it before, in the Seattle area) and whatever happens happens?  It's for a hobby, and I have plenty of other good fry (20+, thinking to take out the adult males).  The goal is to enjoy a happy living tank.

Thanks!

[Guppy tank for my son]

Similar situation with 8 year old and I'm a novice, so it was great to see this thread!

[dwarf aquarium lily]

Newbie here but I'm excited to share how well my dwarf lily and banana plant from coop's doing, see timeline pics below. As amateur gardener, light's everything to a plant. The fuzz went away on its own but the white hair algae was worrying for awhile for a couple of weeks.  (Similar occurred with new driftwood.)  I add in 1 pump of Easy Green with my weekly water changes, don't know how it'd do w/out it, probably fine?  I bought a light online that has 12 hr built in timer.  In the beginning, red dwarf lily was growing almost1 cm a day, it was so exciting.

Side comment, I don't know if banana lily plants normally grow their roots like that so that it'd prop itself up. I'm surprised how much I enjoy aquarium planting.