#4822 · 🐌 snails, slugs & other molluscs
Giant Floater
Pyganodon grandis
8 photos from iNaturalist (Creative Commons) · credits & licences
what is it?
Pyganodon grandis (giant floater) is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is fast-growing, large, and has a short lifespan.
base stats
Bars compare against all animals on log scales: up to 300,000 Dutch and 600,000 worldwide sightings (the most-seen species), 150 t (blue whale), 30 m and 400 years (Greenland shark).
fun facts
- No confirmed wild sightings in the Netherlands on iNaturalist: you'd have to travel for this one.
- 9,945 observations worldwide on iNaturalist.
- Scientifically named by Thomas Say in 1829 (197 years ago).
fact sheet
- English
- Giant Floater
- scientific name
- Pyganodon grandis
- class
- Bivalvia
- order
- Unionida
- family
- Unionidae
- IUCN Red List
- LC · least concern
- sightings in NL
- 0
- sightings worldwide
- 9,945
- GBIF records in NL
- 1
- weight
- —
- length
- —
- lifespan
- —
- named
- 1829 by Thomas Say
IUCN in Dutch: niet bedreigd. Blank means the sources don't say.
relatives· Unionidae
#4621 📷 9Swollen River-mussel
🇳🇱 Bolle stroommossel
Unio tumidus
LC 👀 73 in NL
#4631 📷 8Painter's Mussel
🇳🇱 Schildersmossel
Unio pictorum
LC 👀 54 in NL
#4636 📷 10Swan Mussel
🇳🇱 Zwanenmossel
Anodonta cygnea
LC 👀 46 in NL
#4642 📷 10Duck Mussel
🇳🇱 Vijvermossel
Anodonta anatina
LC 👀 41 in NL
#4707 📷 9Chinese Pond Mussel
🇳🇱 Chinese Zwanenmossel
Sinanodonta woodiana
LC 👀 11 in NL
#4823 📷 7Eastern Elliptio
Elliptio complanata
LC 🌍 9.6k seen
#4837 📷 10Fatmucket
Lampsilis siliquoidea
LC 🌍 7.5k seen
Sources: iNaturalist taxon 130983, Wikidata Q3795937, GBIF 2287951, Wikipedia (EN). Intro text from Wikipedia (CC BY-SA 4.0).Updated 2026-10-24.