Types of Mold: 12 Common Indoor Names and Visual Limits

Why Mold Type Matters

A genus or species name can be useful when a qualified professional has a defined laboratory or building question. It does not replace an assessment of the moisture source, affected material, extent, and access conditions.

Visual labels are limited. Dark, green, white, yellow, and pink growth can each have multiple biological or nonbiological explanations.

Building decisions rely on context. Persistent moisture, major water damage, recurring growth, concealed areas, and damaged porous materials can matter more than color.

Health questions stay separate. A species name or environmental sample cannot determine whether symptoms were caused by mold. Consult a licensed physician for symptoms.

Public cleanup guidance generally focuses on moisture control, affected area, material, and safe handling rather than a color-based health hierarchy. For small, hard-surface areas, our guide to the best mold removal products covers the no-bleach cleaners that fit that guidance.

Black Molds

Stachybotrys chartarum

Appearance: Descriptions often include dark green or black growth on wet cellulose materials. Other organisms and stains can look similar.

Where it may occur: Persistently water-damaged drywall, ceiling tile, cardboard, or wood. A photograph cannot confirm the organism or inspect behind a surface.

Health limit: The name or color does not establish personal exposure or explain symptoms.

Action: Avoid disturbing large, concealed, or heavily water-damaged areas. Ask a qualified professional to define the building scope when safe handling is uncertain.

Cladosporium

Appearance: Dark green to black, suede-like or powdery texture. Forms in circular patches.

Where it grows: Window sills, bathrooms, textiles, carpets, under sinks. One of the most common indoor molds. Also extremely common outdoors.

Identification limit: A dark appearance does not confirm Cladosporium or establish that an area is low risk.

Action: Correct the moisture source and follow current public-health guidance. On small, non-porous areas, a no-bleach product like the one in our Concrobium Mold Control review is a common choice once the moisture is fixed. Use a qualified professional for large, recurring, concealed, or unsafe areas.

Aspergillus niger

Appearance: Black with a white or yellow border. Powdery texture. Grows in dense circular colonies.

Where it grows: Damp walls, decaying vegetation, HVAC systems, and stored food. Very common in homes with humidity issues.

Identification limit: Appearance alone cannot distinguish Aspergillus niger from other dark growth or predict a person's health response.

Green Molds

Penicillium

Appearance: Blue-green to teal, velvety or powdery. Spreads rapidly in concentric rings.

Where it grows: Water-damaged wallpaper, carpet, insulation, mattresses, upholstered furniture, and stored food. One of the fastest-spreading indoor molds.

Identification limit: Blue-green growth is not enough to confirm Penicillium or determine health risk.

Aspergillus (green species)

Appearance: Green, yellow-green, or gray-green. Powdery. Over 180 species exist, and several are green.

Where it grows: Nearly anywhere with moisture: walls, ceilings, HVAC systems, food, soil, and insulation. The most common mold genus found in indoor environments.

Identification limit: Aspergillus is a broad genus. Color and a photograph cannot determine the species, compounds present, or health significance.

Trichoderma

Appearance: White to bright green, cottony or woolly texture.

Where it grows: Damp drywall, wallpaper, wet carpet, and HVAC filters. Grows rapidly on cellulose in high humidity.

Building context: Growth on damp cellulose indicates a moisture condition that should be corrected. Appearance does not establish health effects.

White Molds

White growth is often confused with efflorescence, a mineral deposit associated with moisture moving through masonry. A simple visual or wipe test is not enough to identify unknown material safely.

Early-stage Penicillium and Aspergillus

Some molds may appear white during parts of their growth, but white fuzzy material can also be another fungus, mineral residue, fibers, or debris. Appearance alone cannot confirm an early-stage mold.

Sclerotinia

Appearance: White, cottony. Often found on stored food and in crawl spaces.

Where it grows: Organic materials in damp, cool environments. Common in crawl spaces, basements, and on stored produce.

Building context: A white cottony appearance does not confirm Sclerotinia. Investigate moisture and use qualified identification only when a defined decision requires it.

Pink, Orange, and Yellow Molds

Serratia marcescens (Pink "Mold")

Appearance: Pink to reddish-orange, slimy film. Not actually a mold. Serratia is a bacterium.

Where it grows: Shower tiles, toilet bowls, sinks, pet water bowls. Anywhere with standing water and soap residue.

Identification limit: Pink residue in a wet area is not a medical finding. Follow product-label and public-health cleaning guidance, and correct standing water or persistent moisture.

Aureobasidium (Pink-Black Mold)

Appearance: Starts pink, turns dark brown to black as it ages. Slimy.

Where it grows: Window frames, caulk, wooden surfaces, painted walls. Common in bathrooms and kitchens.

Identification limit: Pink-to-dark growth cannot be confirmed as Aureobasidium from color alone. Use appropriate precautions for unknown biological material.

Fuligo septica (Yellow "Dog Vomit" Mold)

Appearance: Bright yellow, spongy, looks like scrambled eggs. Actually a slime mold, not a true mold.

Where it grows: Mulch, lawns, garden beds. Occasionally found on basement walls near garden entrances.

Identification limit: A photograph may suggest a slime mold, but it cannot confirm the organism or establish health significance.

Why Visual Identification Falls Short

You cannot reliably identify mold species by looking at it. Many organisms, stains, and mineral deposits overlap in appearance.

Visual clues: Color, texture, location, and growth pattern can describe what is visible but are not definitive. Mold Scanner AI provides AI-assisted visual screening of submitted visible surfaces and common lookalikes. It does not identify species.

Surface sample: A properly collected sample may help a laboratory characterize material from one spot. Precision and turnaround depend on the method, sample quality, and laboratory.

Settled-dust analysis: ERMI is a research index based on selected mold DNA in dust. It does not identify every organism in a home and is not a universal safety or health test.

Professional assessment: A qualified professional can combine building history, accessible observations, moisture evaluation, and selected sampling. Building data cannot quantify personal exposure or attribute symptoms.

Browse Mold by Color

Color is a description, not an identification or diagnosis. Each guide below covers visible cues, common building locations, lookalikes, and cleanup limits. Qualified laboratory analysis may characterize a properly collected sample when a defined building decision requires it.