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Discovery stream
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Red Planaria Flatworms
Red planaria are common nuisance flatworms that multiply quickly in low-flow, detritus-rich areas. Heavy infestations can shade and irritate corals, and large die-offs during...
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Acropora-Eating Flatworm
AEFW are Acropora-specific flatworms that eat coral tissue, causing bite marks, poor polyp extension, and slow SPS decline. They spread mainly through unvetted Acropora...
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Montipora-Eating Nudibranch (Phestilla subodiosus)
Montipora-eating nudibranchs are tiny coral predators that chew Montipora tissue, causing “nibbled” edges and scraped white bite patches. They hide on undersides and lay...
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Zoanthid-Eating Nudibranch
Zoanthid-eating nudibranchs are tiny, camouflaged predators that eat zoa polyps and can wipe colonies fast. They hide in mats and lay eggs, so outbreaks...
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Mantis Shrimp (Stomatopoda)
Mantis shrimp are predatory hitchhikers that often reveal themselves through clicking sounds and disappearing snails or hermits. They’re fascinating animals, but not reef-safe in...
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Acropora Red Bugs (Tegastes acroporanus)
Acropora red bugs are tiny parasitic copepods that irritate Acropora, causing reduced polyp extension, dull color, and slowed growth. They spread easily via new...
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Gorilla Crabs
Gorilla/xanthid crabs are common hitchhikers that can become predators in reef tanks, often causing mystery snail and hermit losses. Because many are nocturnal and...
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Ball Anemone
Ball anemones are hardy corallimorph hitchhikers that hide in shaded crevices and feed like tiny ambush predators. They can sting nearby corals and irritate...
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Christmas-Tree Hydroid
Fire/Christmas-tree hydroids are stinging Pennaria colonies that look like tiny feathery “mini trees” on plugs, racks, and sump/overflow surfaces. They can irritate corals—and sting...
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Myrionema Hydroids
Myrionema hydroids are stinging colonial polyps that often spread around zoa mats and frag plugs, causing localized zoanthid irritation and persistent closure. They thrive...
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Hydroids
Hydroids are stinging colonial polyps that hitchhike into reef tanks and can spread across plugs, racks, and rockwork. They often irritate corals and cause...
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Maxi-Mini Carpet Anemone
Maxi-mini carpet anemones are hardy, colorful anemones that like a sandy nook, moderate-to-high light, gentle flow, and regular meaty feedings. They are extremely sticky...
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Marine Ich (Cryptocaryon irritans)
Marine ich is a contagious parasite that causes white salt-grain spots, flashing, and breathing stress in saltwater fish. It often looks less explosive than...
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Marine Velvet (Amyloodinium ocellatum)
Marine velvet is a fast-killing parasite that attacks gills and skin, often showing up as rapid breathing, hiding, and a faint dusty coating. It...
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Brooklynellosis (Brooklynella hostilis)
Brooklynella, often called brook, is a fast-moving external parasite best known for hitting clownfish hard with heavy mucus, breathing stress, and rapid decline. It...
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Uronema (Uronema marinum)
Uronema is an opportunistic protozoan that can cause rapid tissue damage, red sores, and sudden losses in stressed marine fish, especially chromis. It moves...
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Black Ich (Paravortex spp.)
Black ich shows up as tiny dark pepper-like spots, often on tangs, along with scratching and irritation. It is easy to dismiss as sand,...
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Lymphocystis (Lymphocystivirus)
Lymphocystis is a stress-linked viral condition that causes cauliflower-like nodules on fins or skin and usually looks worse than it is. The safest response...
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Vibriosis (Vibrio spp.)
Vibriosis is a bacterial disease that can cause redness, ulcers, frayed fins, and rapid decline in saltwater fish. The safest first move is fast...
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Spirobid Worms (Spirorbidae spp.)
Spirorbid worms are tiny white spiral tube worms that commonly appear in reef tanks and are usually harmless hitchhikers. The main trust challenge is...
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Bristleworms (Eurythoe spp.)
Bristleworms are common reef hitchhikers that usually act as useful scavengers, but their appearance makes people fear them long before they understand their role....
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Predatory Oenone Worm (Oenone fulgida)
Oenone worms are hidden predators often blamed for unexplained snail losses and empty shells in reef tanks. They are hard to catch because they...
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Waminoa Coral Flatworms (Waminoa spp.)
Waminoa are small flatworms that sit on coral tissue and can create chronic irritation, shading, and reduced extension when populations build up. They are...
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Started or starting a saltwater tank. Foundations
A novices to expert on Back to the basics.
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Cycled Yet?
How long does it actually take and what that really even mean?
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Acan Coral (Micromussa lordhowensis)
Acan corals are fleshy LPS corals that usually do well in stable tanks with lower to moderate light, gentle flow, and some space from...
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Bearded Fireworm (Hermodice carunculata)
Bearded fireworms are not the same thing as ordinary bristleworms. They can sting, irritate coral, and sometimes eat weakened inverts, so the right move...
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Bobbit Worm (Eunice aphroditois)
Bobbit worms are hidden ambush predators that live deep in rock or sand and can cause strange fish, snail, or crab losses. They are...
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Bubble Coral (Plerogyra sinuosa)
Bubble coral is an LPS coral that does best in lower to moderate light, gentle indirect flow, and a spot where it can expand...
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Coral-Boring Spionid Worms (Spionidae spp.)
Coral-boring spionid worms live in or around coral skeleton and feed with paired filaments that can irritate tissue and contribute to localized recession. They...
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Eye/Skin Flukes (Neobenedenia melleni)
Eye and skin flukes are contagious external parasites that can cause flashing, excess mucus, cloudy eyes, and chronic irritation. They are often missed because...
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Marine Leeches (Piscicolidae; e.g., Trachelobdella spp.)
Marine leeches are visible external parasites that attach to fish, feed on blood or tissue, and leave behind wounds and stress. Seeing one on...
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Montipora Cap (Montipora capricornis)
Montipora capricornis is a plating SPS coral that can grow quickly into shelves and scrolls when the tank is stable. It is usually manageable...
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Green star polyp
GSP Green star polyp care.