Aging? (and new axies)

Ive had my axie (speedy) for about 2 years and ten months and he is 23cm long (or just 9 inches) and he is pretty well fed. is there any kind of way i can estimate his age? because i dont know old he was when i got him, but i do remember he was about 15cm (6 inches) when i first got him

also, he has lived alone the entire time and ive just gotten another one and im a little wary of puttin them together in the same tank. this new fish is about 16cm (6.5 inches) but considerably skinnier and scrawnier than the first one. at the moment i have a piece of glass down the middle of the tank to seperate them because ive been told that axies can be a bit cannablisitic. so does anyone know when its a safe time to take the glass out? and does anyone know how old speedy might be?
thanks heaps and sorry about the length!!

hi Im not sure about the age, but mine was about 3-4 inches around maybe 4-6 months old i think, now he's 8-9 inches and is 2. he has been that big for about a year or a bit more. I just got another one too, sounds exactly the same, turned out to be female and less than a week later we have eggs!!!! Good Luck!

Natalie, there's no way to be sure, but 6 inches is usually obtained between 6 months and a year.

I would keep the new one seperate until it has put on weight and you think it can fend for itself.

Also, next time, I would not put a new axolotl in with an existing tank until it has been quarantined for at least 30 days. Otherwise you run the risk of introducing disease into your new tank.

They are cannibalistic when they're young, but adults won't eat other adults (they're just too big to swallow).

well, i actually went away for 2 days over christmas and when i got back i went to check on them and the little one had somehow (amazingly) managed to wriggle through the partition and was snuggled up with my other axie! its been pretty much like that since so i think they must be best friends! thanks for the help tho!