Here’s a detailed comparison to help you distinguish between the eggs (spawn) and tadpoles of the Australian green tree frog (Ranoidea caerulea) and the invasive cane toad (Rhinella marina).
Eggs (Spawn)
Feature
Green Tree Frog (Native)
Cane Toad (Invasive)
Appearance
Laid in foamy clumps or jelly-like masses
Laid in long, transparent jelly strings
Structure
Eggs often in clusters, sometimes foamy
Eggs form double rows in a gelatinous string
Location
Floating on surface or attached to vegetation
Strands often wrapped around plants, submerged
Egg Color
Varies, but not in bead-like strings
Tiny black eggs, bead-like in appearance
Quantity
Hundreds to a few thousand per clutch
8,000–35,000 eggs per clutch
Protection
Foam or jelly helps prevent drying and predation
No individual casing, less protected
Key ID Tip: Green tree frog eggs are in clumps or foamy masses; cane toad eggs are always in long, bead-like gelatinous strings.
Tadpoles
Feature
Green Tree Frog Tadpoles
Cane Toad Tadpoles
Color
Brown, sometimes with visible veins in tail
Shiny jet black on top, blue-grey/black belly
Shape
More elongated, tail fin slightly veined, pointy tip
Oval-shaped, broad, with a pointed snout
Tail
Tail fin slightly marked with veins, pointy tip
Transparent fin, short tail
Behavior
Often solitary or loosely grouped
Swarm in large, slow-moving groups
Size
Generally larger than cane toad tadpoles
Small (up to 3 cm), usually smaller than frog tadpoles
Breathing
Come up to surface to breathe
Rarely surface to breathe
Toxicity
Non-toxic
Highly toxic at all life stages
Key ID Tip: Cane toad tadpoles are small, black, and form dense groups; green tree frog tadpoles are brown, larger, and more solitary.
Summary Table
Stage
Green Tree Frog (Native)
Cane Toad (Invasive)
Eggs
Clumps/foam/jelly masses
Long, bead-like gelatinous strings
Tadpoles
Brown, larger, pointy tail tip
Jet black, smaller, oval, group together
Other Notable Differences
Toxicity: Cane toad eggs, tadpoles, and adults are all toxic to most native predators, while green tree frogs are not.
Ecological Impact: Cane toads breed prolifically and their young outcompete and poison native species, including green tree frogs.
In summary: Green tree frog spawn appears as clumps or foamy masses, and their tadpoles are brown and somewhat solitary. Cane toad spawn is laid in long, bead-like strings, and their tadpoles are small, shiny black, and gather in dense groups-plus, they are highly toxic at all stages.
To prevent mold growth in a bioactive terrarium, follow these best practices:
Start Clean: Wash your container, decorations, and all materials thoroughly before setup to eliminate mold spores and pathogens.
Use Mold-Preventing Materials: Incorporate sphagnum moss and activated charcoal in your substrate or as a layer; both help absorb excess moisture and inhibit mold growth.
Add a Cleanup Crew: Introduce springtails (and isopods if appropriate) early on. Springtails are highly effective at consuming mold and keeping it in check, acting as a natural, ongoing defense.
Springtails
Maintain Good Ventilation: Ensure your terrarium has adequate airflow by adding ventilation holes or mesh, or by periodically airing it out. Mold thrives in stagnant, humid air.
Monitor and Control Moisture: Avoid overwatering and allow the substrate’s surface to dry out slightly between mistings. Mold outbreaks are often triggered by excessive moisture.
Remove Debris Promptly: Regularly remove dead plant material, uneaten food, and decaying matter, as these are prime food sources for mold.
Limit Biodegradable Decor: Avoid excessive use of sticks, seed pods, or other biodegradable items that can quickly rot and fuel mold outbreaks in humid conditions.
Supplement with Beneficial Microbes: Consider adding commercial inoculants of beneficial fungi and bacteria to outcompete mold species.
Light and Temperature: Ensure the terrarium is well-lit and at appropriate temperatures for your species; good lighting can help suppress mold.
Manual Removal: If you spot mold, remove it manually or treat small patches with a diluted hydrogen peroxide solution (1:1 with water) to kill it safely.
Key tip: A small amount of mold is normal in new setups and usually resolves as your bioactive system matures and your cleanup crew becomes established. Persistent or aggressive outbreaks may indicate issues with ventilation, moisture, or an underperforming cleanup crew.
In summary: The best prevention is a combination of clean setup, proper moisture and airflow management, and a robust population of springtails and other beneficial microfauna.
