10 Most Unwanted Aquatic Invasive Species

Vocabulary flashcards covering each of Arizona’s 10 most unwanted aquatic invasive species and the key prevention slogan.

Quagga & Zebra Mussels

Small bivalves from Eastern Europe/Ukraine that rapidly colonize, strip nutrients from the water, clog pipes and boat engines, and are spread by boats, live wells, and water infrastructure.

Rusty Crayfish

Aggressive crayfish from the Ohio River Basin used as bait that out-competes native fish for food and cover; voracious and cannibalistic, it spreads via bait buckets and aquarium dumps.

New Zealand Mudsnail

Tiny snail from New Zealand that out-competes native snails, reproduces quickly, and hitchhikes on fishing gear, waders, and vegetation attached to boats.

American Bullfrog

Large frog native to the eastern U.S.; introduced through stocking and the pet trade, it preys on nearly all aquatic life, threatening many endangered amphibians and fish in Arizona.

Asian Carp (Bighead, Black, Silver)

Heavy-bodied carp from Eurasia/China introduced for algae control; they jump when startled, out-compete young sportfish for plankton, and spread through bait buckets and illegal stocking.

Northern Snakehead

Voracious predatory fish from China/Korea that can reproduce up to five times a year and aggressively guard young; potential threat to sport fish if introduced, usually spread by dumping live fish or eggs.

Giant Salvinia

Floating South American fern that forms thick surface mats, blocks light and oxygen, impedes water flow, and is spread by boats, trailers, and downstream drift.

Didymo (Rock Snot)

Algae from Northern Europe/North America that creates dense stream blooms, smothering habitats and food sources for fish; transported on boats, waders, and fishing gear.

Hydrilla

Fast-growing submerged plant from Eurasia/Africa/Australia that can grow an inch a day, ‘top out’ at the surface, shade out natives, clog canals, and spread via plant fragments on boats.

Red Claw Crayfish

Australian crayfish farmed for food that is highly tolerant, prolific, cannibalistic, and damaging to native fish and habitats; spreads through bait dumping and illegal stocking.

“Stop Aquatic Hitchhikers”

Arizona’s prevention message urging boaters and anglers to clean, drain, and dry watercraft and gear, avoid releasing pets or live fish, and remove plant fragments to curb invasive spread.