Whenever I see a +1/+1 counter style Atraxa deck, I always ask the same quest, where's the Sage of Hours at? Also, you took Mirrorweave out, which would make this little trick make the entire table groan. Finally, the Eldrazi Displacer is spectacular in conjunction with the doubling fish. Just a couple thoughts.

Yeah, I briefly made it a three color deck and couldn't run mirrorweave, but I meant to put it back in. I actually had sage of hours in an earlier version of this, and cut it for strionic resonator. What would you cut to put him back in?

Honestly, get rid of Mycoloth. I play Atraxa all the time and have three builds I like to play: +1/+1 counters, infect, and token strategy. The Mycoloth is pretty bad unless you're going straight tokens because you're giving up your board for one big beater that will give you back your board over several turns. I've never gotten much value out of it before it dies due to spot removal or board wipes. I've yet to get less than 2 extra turns out of my Sage before it bites the dust.

Cut Mycoloth for Sage of Hours, and made a lot of other changes.

I found another solid inclusion out of the Aether Revolt cards that I started running, and it's really paying dividends: Ridgescale Tusker, Skyship Plunderer, and Lifecrafter's Bestiary, i.e. the Pokedex. Tusker is for obvious reasons, and in order for you to proliferate, you need to have counters spread out. The Plunderer is basically a targeted Thrumming bird, in essence. Not nearly as powerful, but it's an early threat with evasion that works well with what we're trying to do. Finally, the Pokedex! I'm sure everyone can agree that Green is terrible at card draw. Atraxa gives us access to blue and black, but having a free scry every turn and Whispers of the Muse just for playing a creature (except for ) isn't a bad deal.

I've been running these new cards and when you come across them, especially early on, they are busted. Recommendations for removals would be Ghave for Tusker, Pokedex for Archmage, and I'm not sure about the Plunderer. I would say that your curve is very 4 CMC heavy with very little ramp. I try to discourage people from rely a lot on artifact mana simply because so many people run stuff like Vandalblast or Shattering Pulse. You may consider trying to find a place for Farseek, Kodama's Reach, Cultivate, and/or Explosive Vegetation. Those are just a few observations.