I cant figure out why my axolotls gills aren't fluffy

[MyLittleComet]

I finally tested their water hardness, thinking maybe it was too soft and that could be effecting it, but its perfectly within range! (Gh 125 ppm) the rest of their parameters are where they should be as well, ph, ammonia, nitrite and nitrate... I dont get it. I feed them Hikari carnivore pellets every other day as they're all adults, as much as they'll eat (I've tried giving them worms recently and they wouldn't eat them). They all have sponge filters so there's no current bothering them, they all have air stones too to keep the ph where it should be. Why does everyone else's axolotls seem to have bigger fluffier gills?
I know it's partially genetics, but all three of them are from different places and they all have the same problem, which leads me to think I must be doing something wrong...

 

[wolfen]

gh is general hardness which is calcium and magnesium, at 125 it is at the lower end of ideal (7.3) ideal is 7 - 14, at under 8 it is considered soft info here Water Quality Explained: How It Can Affect Your Axolotl's Health - WSAVA 2015 Congress - VIN , what are the other parameter readings.
your golden albino looks like there may be signs of fungus on the gill tip.
look into using holtfreters solution or a modified version to improve water chemistry and make the water more comfortable info here Axolotls - Requirements & Water Conditions in Captivity