Super active axolotl?

So I've had 8 axolotls and the first 7 all acted typical, lazy, etc. but my latest is a little dude about 3.5" and he's SUPER active. Like, swimming back and forth and up and down regularly. He'll swim across the tank (20 gallon long) and stop for maybe 30 seconds, then swim back, and regularly goes up for air. Though I'll say he doesn't do it all the time and does take breaks and just chills in his java moss hut for good periods of time as well. His tank is 66 degrees F, the current is low, the parameters are all clean as can be. No bright lights or anything like that. His gills aren't curled and he's eating well. Everything is solid, I'm an experienced keeper and have been taking great care of him. I usually don't ask about stuff like this and I try not to be a hypochondriac but it does seem a bit peculiar.. Has anyone else had an axolotl who just seemed hyper and restless? I'm an experienced owner and can't think of anything that could be particularly wrong with him. My avatar is him.

Sounds like it is just his personality . I wouldn't be too concerned if all the parameters are in check and he is eating and pooping normally and is not seeming stressed. But I know what you mean. I am a terrible hypochondriac with my pets and always making mountains out of molehills

My little dude has always been active.

Every morning i will get up and see him patrolling the corners of the tank. He swims quite fast and he always crashes face first into the corner like its a complete surprise the corner is there then he turns around and off he goes again.

He's about 2.5 years old now and has been doing this for at least a year. Sometimes his tail will turn pink from swimming so much and then he'll chill out in the evenings.

I used to have a lot more in his tank but he seemed to enjoy swimming so much i took everything out and just left a cave in the middle so he can patrol the back or front of the tank at his leisure.

I was worried at first because everyone was saying they are supposed to be lazy but Limbo has always been this way. When he stops patrolling the corners each day, thats when i'll worry

Is he a wild type? I've noticed both my wild types tend to swim near the surface a lot more than my leucistic or golden albino.

Sometimes water quality issues make them swim more, but you've already mentioned that your water is fine.

Also, I've noticed smaller juvies tend to swim more. Once they reach a certain size (around 6-7 inches) they swim less and crawl around on the bottom more.

My guys are all about 7 inches. The wild type likes to climb up plants and ornaments, or perch in leaves near the surface for periods. The others tend to spend their time near the bottom, but are still active in other ways (climbing, rolling moss balls etc.)