Pastel Mermaid Hair help?! (pink-purple-blue-turquoise)

How light did you bleach for the pink? Is the yellow coming from your base or the pink dye?
For cool toned pastels you need as little yellow in your base as possible.

I can't really remember but probably varying levels 7-8-9,  3-4 inches of my roots were bleached to a banana yellow color but I put more atomic pink on top which created this peachy mess. The ends of my hair are very pastel pink.
Would I need to bleach even more? I've just did bleach bath last week and it only got peachier ):

Atomic pink is notoriously difficult to remove. It also has a lot of warm tones which will be contributing to the peach effect.
For pastels you really need an even level 10 base. You can get away with slightly darker for the aqua colour, as the yellow in your hair will contribute to the green shade.
The ends look great, but you will probably have to bleach any darker areas.
Getting rid of the pink will be tricky though, i would try a colour remover next. Use it on clean, clarified hair, keep it covered and warm.

Oh tell me about it ): I honestly believe it may have stained my hair cuticle! I've done multiple vitamin c treatments, dish soap, I've bleached bath twice so far and had to cut some hard earned length off ): I think I may give up and just stick with the pink at this point haha or perhaps do the multiple colors just far less diluted to cover up all the peach?

Try color b4 extra strength (color remover) i had excellent results removing stubborn pink with it. Make sure you clarify your hair well before.

I've also used a color remover ): I used Color Zap! It was like a mild bleach, it barely dented the color much and just caused damage :/

That is a colour stripper, completely different from a colour remover. Colour removers work by shrinking the dye molecules so they can be washed out of the hair, they are totally non-damaging so definitely worth a try.

Oh really?! I didn't know there was a difference! I'll definitely try it out soon and keep you guys posted!

I usually dye in layers,  and go with a regular color scheme.  I have issues getting my hair very pale blonde because my hair is naturally very dark brown.  I either end up with red streaks,  or chunks of blonde,  or destroyed hair. But my colors come out vibrant (I'm cheap and use splat hair color). If your hair isn't layered,  it may be difficult.  Do one color at a time,  starting underneath. 

ended up covering my whole head up with atomic turquoise and shocking blue manic panic (:
Color came out awesome I'll post a pic ASAP!