Learning Objectives
By the end of this lesson, learners will be able to:
- Understand why mould and fungus naturally appear in new bioactive vivariums.
- Identify harmless vs. harmful mould types.
- Manage mould safely without damaging the bioactive system.
- Support microfauna so they outcompete fungal blooms.
- Prevent severe fungal outbreaks through balanced humidity and ventilation.
Lesson Content
Mould and fungus are extremely common in new bioactive setups.
They are not a sign of failure — they are a normal part of ecological cycling, especially in the first 2–8 weeks.
Most mould blooms disappear naturally once microfauna populations (springtails, isopods, beneficial microbes) increase.
This lesson will teach keepers how to distinguish normal fungal growth from problematic outbreaks and how to manage each safely.
1. Why Mould Appears in New Tanks
When natural materials like:
- leaf litter
- wood
- bark
- moss
- substrate blends
are exposed to moisture, fungi colonise them.
This is the start of decomposition — a normal, healthy process.
Mould appears because:
- the environment is moist and warm
- microfauna populations are still small
- wood and leaves release sugars as they hydrate
- beneficial bacteria and fungi are not yet balanced
This is called the “bioactive bloom” stage.
2. Harmless Mould Types
Most moulds in vivariums are harmless and temporary:
A) White, fluffy mould
Common on new wood and leaves.
Disappears once springtails populate the tank.
B) Thin fungal threads
Look like fine white hairs.
Break down organic matter.
C) Surface biofilm
Slight slimy or glossy patches.
Normal and consumed by microfauna.
D) Dusty pollen-like growth
Usually beige or tan.
Breaks down bark and lignin.
All of these will be eaten by microfauna and should not be manually removed unless excessive.
3. Problematic Mould Types
Rare, but important to identify.
A) Thick, rapidly spreading mould
- grows aggressively over leaves
- forms thick patches
- not reduced by springtails
- often caused by stagnant air
B) Strong-smelling fungal growth
Healthy fungus does not smell.
A sour or rotten smell indicates anaerobic decomposition.
C) Brightly coloured moulds
Uncommon but possible:
- green
- blue
- orange
These may indicate contamination.
D) Large patches in areas with poor ventilation
Usually caused by airflow imbalance.
Problematic mould is still manageable but requires intervention.
4. How to Manage Normal Mould Safely
A) Increase springtails
Add extra springtail cultures directly to:
- wood
- leaf litter
- substrate edges
They will rapidly consume the mould.
B) Add isopods
Dwarf white, dairy cow, or tropical species accelerate decomposition and outcompete fungi.
C) Improve airflow slightly
- open ventilation by 5–10%
- ensure cross ventilation
- raise light slightly to increase convection
Do not over-ventilate — that causes humidity crashes.
D) Allow time
Most normal mould disappears within:
- 7–21 days for mild blooms
- 3–6 weeks for strong early blooms
Patience is often the best tool.
5. How to Fix Problematic Mould
Step 1 — Remove most of the infected material
- lift out mouldy leaf litter clusters
- trim heavily affected moss
- wipe thick fungal mats with a damp paper towel
Do NOT remove everything; remove only the excess.
Step 2 — Increase ventilation temporarily
Raise airflow for 48–72 hours, then return to normal.
Step 3 — Add microfauna heavily
- seed twice the normal amount of springtails
- add isopods directly under the mould patches
Microfauna is your best defence.
Step 4 — Reduce misting for 3–5 days
Allow the surface to dry slightly while maintaining substrate moisture.
Step 5 — Check for overheating
Mould thrives in hot, stagnant pockets.
Ensure:
- lights are not heating the top layer
- airflow pathways are open
6. Preventing Severe Mould in the Future
A) Rinse wood and leaves before use
Removes sugars that cause aggressive mould.
B) Bake or boil wood if necessary
Kills mould spores and sanitises surfaces.
C) Seed microfauna heavily at the start
Prevents the “mould advantage”.
D) Avoid overmisting new setups
Plants and substrate need time to adjust.
E) Use good ventilation design
Crossflow helps prevent stagnant pockets.
7. Is Mould Dangerous to Frogs?
In almost all cases:
No — not directly.
Mould is part of a natural breakdown cycle.
However, mould may indicate:
- poor ventilation
- excessive misting
- unstable microfauna populations
Fix the underlying issue, not the mould alone.
Key Takeaways
- Mould is normal in new bioactive setups and usually harmless.
- Most moulds are eliminated naturally by springtails and isopods.
- Serious mould grows thick, spreads fast, or smells bad.
- Fix mould by balancing microfauna, airflow, and hydration.
- Mould rarely harms dart frogs directly but can signal a deeper issue.
