Google "pink mold on marble". You'll find a number of solutions to the problem.

we get pink mold on everything in the shower, regardless of the material. it's extremely easy to scrub away -- but do it before it gets worse!

also... is the grout not sealed? I thought that was necessary no matter where it's installed.

Ughhhhhh!!! What the heck. Where does pink mold come from!? What is the best cleaner? And sealer?

IDK about sealers, call a tile store and ask. but for the pink mold: I only need to use soap, vinegar, or windex + light scrubbing. it's really easy to get out if you catch it early. but if it's getting deep in your grout, you might need to spray it with bleach water and let it sit.

it's possible that your grout is sealed and the pink mold is just sitting on top. try the gentlest cleaning / scrubbing methods you can before getting more aggressive.

It’s a brand new shower. I tried getting it off earlier and it came right off but it’s sad to me it’s even there :(. Will have to do something about it. I’ll have to seal it. Always something right... shoot!

Ask the person who did the tile job if they did seal it or not. The thing is, pink mold is pretty typical. is this something that wasn't happening before the new shower redo? does it seem like water is sitting too long in some areas, not draining well enough?

Vinegar or bleach may etch marble tile. Not appropriate marble cleaners.

Bleach, vinegar and windex might not be the best option if you have marble. They can damage/etch the stone. I get orang/red on my shower tile from iron in the water and get it off with just Dawn and a sponge.

@hcbm any suggestions for cleaning products?

On the advice of dragonfly who is a professional who posts often, I use MB Stone Care

They have a line of different products.

I have a marble shower which was installed when I remodeled in October 2018 and have had no mold issues of any color :-)

Several things to consider

How is the ventilation in your bathroom. I have a Panasonic Whisper fan which operates automatically based on ambient humidity in the room. I don't even have condensation on my mirrors

What kind of soap do you use to clean yourself? Liquid shower soap should be used and not bar soap because bar soap has ingredients which tend to stick to the surface of the shower which would be especially important for a marble shower

Is your shower draining properly? There is absolutely no water lingering around my drain after I turn off the water except for some slight residual moisture which my exhaust fan eliminates quickly.

No I don't have any marble in my home. I would ask the manufacturer. Or post a new thread asking about safe marble cleaners. You will receive many answers. Good luck.

You have inadequate ventilation and aren’t cleaning the shower often enough. pH neutral stone cleaners only. And squeegee every time.

Showers need cleaning all the time , a squeegee after every shower a mild soap and a micro fiber cloth at least once a week for a thorough cleaning and if a busy shower maybe more often.

HCBM, Thanks for that info on pink slime, as I call it. I figured it was not a mold, and now I know! I get it in the grid cut into my solid surface shower floor. I use Force of Nature, an electrolyzed water disinfectant, and it kills it dead. Their webpage says it can be used on sealed stone, including marble. I simply use a scrub brush on a mop stick to loosen anything left behind, then rinse and I am good for weeks. I do have good ventilation, so I think that it is simply where the skin cells fall. The OP likely has the same thing, skin cells settling into the indentations (which are grout lines in her shower).

I really like the Force of Nature system. It is a small counter-top base with a bottle for making the solution, then a spray bottle. You buy their ampules of vinegar and salts and squirt them into tap water in the bottle, put the bottle on the base, and hit the button to start the system. It makes 12 oz at a time and the solution lasts 2 weeks. You can use it on just about every surface. It does fade natural dyes, I have found, so you can't use it on certain fabric. But it kills all bacteria and viruses by mechanically breaking their cell walls, so that it is not something that the organisms can become immune to. Force of Nature (currently on sale, too)