Large amounts of axolotls cause performance issues

Does this still occur if the axolotls are spawned in water instead of on land?

Yep

did you think that too many entities cause lag?

and axolotls are new ,not tottaly finnished there so it has not had a performance update

It is logical that such a number of mobs will cause terrible lags. However, compared to the same foxes, axolotls significantly degrade performance. Just because they're new doesn't mean anything.

Can confirm.

I tested this with a command block spawning around 250 to 300 mobs in a superflat world and axolotls caused basically double the impact of other tested mobs: turtles averaged 11 ms, foxes averaged 12 ms, bees averaged 10 ms and axolotls averaged 22 ms.

Maybe it’s becouse axolotls are trying to pathfind to water, something other mobs don’t do

I don't think that is the main cause, because as far as I know turtles also attempt to pathfind to water. Also, the lag happens even when the axolotls are already in water.

In 1.17