Bognook Glossary
Amphibian keeper terms, explained
Every hobby has its jargon. Here are the amphibian-keeping words in plain language — no gatekeeping, no assumed knowledge. 36 terms, each linked to the guide or tool that goes deeper.
Updated July 2026
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🧬 Biology
- CloacaVentThe cloaca (or vent) is the single opening on the underside near the tail that an amphibian uses for waste, mating and egg-laying — and its shape is often how you sex adults.
- EftAn eft is the juvenile, land-living stage of a newt — the phase between the aquatic larva and the semi-aquatic adult, when the young newt lives on land with dry, often brightly-coloured skin.
- External gillsExternal gills are the feathery, branch-like gills that stick out from the sides of the head on neotenic salamanders like the axolotl, letting them breathe underwater for life.
- MetamorphosisMetamorphosis is the transformation an amphibian goes through from an aquatic, gilled larva into its adult form — for example a tadpole becoming a froglet, or a larval salamander losing its gills and moving onto land.
- MorphA morph is a colour and pattern variant of a species — like a leucistic, albino or copper axolotl — produced by genetics, without changing the animal's care needs.
- NeotenyPaedomorphosis · NeotenicNeoteny is when an amphibian keeps its juvenile, gilled, fully-aquatic body for its whole life instead of metamorphosing onto land — the axolotl is the classic example.
- Permeable skinCutaneous respirationAmphibians have thin, permeable skin that absorbs water, oxygen and — unfortunately — toxins, soaps and salts, which is why clean water and clean, wet hands matter so much.
- WaterdogA "waterdog" is a larval (gilled, aquatic) tiger salamander, often sold as bait or mistaken for an axolotl — but unlike an axolotl it will eventually metamorphose and leave the water.
🩺 Health
- ChytridChytridiomycosis · BdChytrid (chytridiomycosis, caused by the fungus Bd) is a devastating amphibian skin disease that disrupts the skin's ability to breathe and balance salts, and is a major driver of amphibian extinctions worldwide.
- DropsyEdema · BloatDropsy (edema) is a swollen, bloated, sometimes "pinecone" appearance caused by fluid building up in the body — a serious sign of an underlying problem that needs a vet.
- ImpactionImpaction is a blockage of the gut, most often from an amphibian swallowing loose substrate (like gravel) along with its food — a common, avoidable, and potentially fatal problem.
- Metabolic bone diseaseMBDMetabolic bone disease (MBD) is a weakening and deformation of the skeleton caused by a lack of calcium or vitamin D3, leading to soft, bendy bones and a "rubber jaw".
- Parotoid glandsParotoid glands are the large toxin-secreting glands behind a toad's eyes (and on some salamanders) that ooze an irritating-to-toxic defence when the animal is threatened.
- QuarantineQuarantine is housing a new or sick amphibian separately, in a simple bare setup, for several weeks before it goes near your other animals — to catch disease before it spreads.
- RanavirusRanavirus is a group of viruses that cause sudden, often fatal disease in amphibians (and reptiles and fish), spreading rapidly and sometimes wiping out whole ponds or collections.
- Red-legRed-leg is reddening of the skin on the belly and legs caused by a bacterial infection (often a sign of septicaemia) — a genuine emergency that needs a reptile/exotics vet.
🏠 Setup
- BioactiveA bioactive vivarium is a living, self-cleaning setup where a "cleanup crew" of tiny invertebrates and live plants break down waste, so the enclosure largely maintains itself.
- Cleanup crewCUCThe cleanup crew (CUC) is the team of tiny invertebrates — usually springtails and isopods — that live in a bioactive vivarium and eat mould, waste and dead plant matter.
- IsopodsIsopods are small land crustaceans (like woodlice / roly-polies) used in bioactive vivariums to break down waste and dead plant matter, and as an occasional calcium-rich feeder.
- SpringtailsSpringtails are tiny (~1 mm) soil invertebrates that eat mould and decaying matter, forming the smallest, most important part of a bioactive vivarium's cleanup crew.
- SubstrateSubstrate is the material on the floor of the enclosure — for most terrestrial amphibians a soft, moist, non-swallowable bedding like coco fibre or topsoil (never gravel).
💧 Water
- DechlorinatorWater conditionerA dechlorinator (water conditioner) is a product that neutralises the chlorine and chloramine in tap water, which are toxic to amphibians and to the beneficial bacteria in a cycled tank.
- Nitrogen cycleCycling · Ammonia · Nitrite · NitrateThe nitrogen cycle is the process of growing beneficial bacteria in a tank's filter that convert toxic ammonia (from waste) into nitrite and then far less harmful nitrate — a tank is "cycled" once this is established.
- Water hardness & pHGH · KH · pHWater hardness (GH/KH) and pH describe the mineral content and acidity of tank water — parameters that matter because amphibians like axolotls need moderately hard, stable, near-neutral water.
🍽️ Feeding
- DustingSupplementationDusting is coating feeder insects in a fine calcium (and sometimes vitamin/D3) powder just before feeding, to supply minerals amphibians can't get from insects alone.
- Feeder insectsFeeder insects are the live invertebrates — crickets, dubia roaches, black soldier fly larvae, worms and flightless fruit flies — that make up most insectivorous amphibians' diets.
- Gut-loadingGut-loading is feeding your feeder insects a nutritious diet for 24–48 hours before offering them, so the nutrients pass on to your amphibian.
🔄 Behaviour
- AestivationAestivation is a dormancy triggered by heat or dryness rather than cold — many frogs and toads dig down (and some form a protective cocoon) to wait out dry conditions.
- BrumationBrumation is a reptile-and-amphibian version of hibernation — a cold-season slow-down where the animal becomes inactive and stops eating in response to cooler, shorter days.
- FossorialFossorial means burrowing — a fossorial amphibian spends much of its life dug into the substrate, so it needs a deep, soft, moist layer it can disappear into.
🥚 Breeding
- AmplexusAmplexus is the mating embrace in frogs and toads, where the male grips the female from above so he can fertilise her eggs as she lays them.
- FrogletA froglet is a newly metamorphosed young frog — just off the water with four legs and a shrinking tail stub — and the most delicate stage to raise, needing tiny food and high humidity.
- Nuptial padsNuptial pads are dark, roughened patches that male frogs, toads and newts grow on their thumbs or forelimbs in breeding condition, used to grip the female during amplexus.
- SpawnSpawn is the mass of eggs an amphibian lays — frog spawn in clumps, toad spawn in strings, and many salamanders and newts attaching eggs singly to plants.
- TadpoleA tadpole is the aquatic, gilled larva of a frog or toad that hatches from spawn and gradually grows legs, absorbs its tail, and metamorphoses into a tiny froglet.
🌿 Ethics
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