Hello!
That looks interesting. Don't worry about being a bad owner. We've all been there.
From the pictures it looks like a bacteria bloom, but if you say it's hair-like, I'm not sure.
Do you know your water values (ammonia, nitrites, nitrates, pH)? That would help.
How about temperature? Could it be that the water has suddenly warmed (possibly due to summer)?
Most important, though: do the axolotls look affected by it? Any changed behaviour, or stress signals (sudden floating, bright gills, lethargic or lazy behaviour)?
