Cactus Alga

Dead Man's Fingers

Gutweed

Feather Algae

Green Bubble Algae

Sea Grapes

Green Sea Grapes

Saw Caulerpa

Hula Skirt Algae

Chaeto

Killer Alga

Feather Caulerpa

Halimeda

Sea Lettuce

Mermaid's Fan

Shaving Brush Alga

Alien Fingers Alga

Peacock's Tail

Articulated Coralline Alga

Common Coralline Alga

Magician zoanthids

King Kong Yuma mushroom

Elegance coral

Kryptonite candy cane

Exosphere zoanthids

Hologram hammer

Stratosphere zoanthid

Orange oxide zoanthids

Glow worm goniastrea

Cornflower goniopora

Acropora microclados

Acropora robusta

Lunar eclipse zoanthids

Iron man goniopora

Laser lemon zoanthids

Splatter hammer

Sakura sunrise zoanthids

Orange plate coral

Green star polyps

Tropic thunder montipora

Blue Velvet Damselfish

Paccagnella's Dottyback

Blue hippo tang

Sailfin Tang

Ocellaris Clownfish

Blue Tang

Flame Angelfish

Yellow Tang

Six Line Wrasse

Neon Goby

Pink Spotted Watchman Goby

Melanurus Wrasse

Blackcap Basslet

Possum Wrasse

Black Ice Clownfish

Dispar Anthias

Potter's Angelfish

Blue Assessor

Geometric Hawkfish

Blue Spotted Jawfish

Visually striking and consistently one of the hardest inverts to keep alive long term — that combination should tell you something.

They are filter feeders that need phytoplankton and zooplankton in quantities most display tanks cannot sustain naturally.

Without supplemental target feeding multiple times a week, they slowly starve over months while looking fine.

Buy one if you are committed to the feeding schedule — otherwise it is a beautiful short-term guest.

Flame Scallop

Long spider-like legs and a body that looks like it crawled out of a sci-fi film — nothing else in the hobby has this silhouette.

Great at hunting bristleworms, which is genuinely useful in a reef.

The catch: it will eventually go after small ornamental shrimp once it's comfortable, and "eventually" usually means within a few months.

Keep it fed with meaty foods and keep it away from anything small and expensive.

Arrow Crab

One of the more dangerous inverts you can add to a reef — when stressed or dying they release toxins that can wipe out everything in the tank within hours.

They need very stable water, consistent particulate feeding, and no aggressive tankmates that can provoke an evisceration response.

That evisceration — expelling the gut when threatened — is the specific event to prevent, and it can be triggered by stress alone.

Experienced keepers with appropriate systems and overflow baffles manage them successfully, but this is not a casual addition to any reef.

Sea Apple

The most dangerous animal in this entire database — a large Carpet can eat a full-sized clownfish, small wrasses, and anything else that wanders over it, silently and fast.

They need serious light, serious flow, and regular feeding with large meaty chunks.

The hobbyists who keep these well specifically build a tank around one; the ones who buy it on impulse as a clownfish host have $200 worth of dead fish within a month.

Carpet Anemone

Incredible sandbed cleaners that process waste and detritus constantly — pound for pound one of the best biofilter additions for a mature system.

The caution rating is about what happens if they get stressed or die: they release potent holothurin toxins into your water that can wipe an entire tank fast.

Don't let powerheads near them, acclimate slowly, and if one starts looking pale and deflated get it out of the tank immediately.

Black Sea Cucumber

One of the most stunning things you can add to a reef — those double spiral crowns in red, blue, orange, and yellow are breathtaking, and they retract instantly when a shadow passes.

They're always embedded in live coral when you buy them, usually Porites, so you're committing to keeping that coral alive too.

Don't move the rock they're on; disturbing the base usually kills them.

Christmas Tree Worm

The original cleaner shrimp of the hobby — bold, interactive, and they'll actually set up a cleaning station that fish learn to visit.

You need to keep only one, or a bonded pair, because they'll fight to the death otherwise.

They're harder on small tank mates than most people expect for something rated "semi-aggressive," so watch them around ornamental shrimp under an inch.

Banded Coral Shrimp

One of the most visually striking things you can put in a large FOWLR — that pillow shape and bold orange-red coloration genuinely makes people stop and stare. The problem is it's an eating machine: it will work through every snail, small clam, and chunk of microfauna your sandbed has ever grown, then starve once it's cleaned house. People always underestimate how much they eat. If you're running a mature 125+ gallon FOWLR with a deep sandbed and don't mind restocking clean-up crew regularly, it's worth it for the spectacle — but put it in a reef and you're just paying to feed it corals.

Cushion Starfish

Big, colorful, cheap — the Florida Keys staple that's been in the hobby longer than most of us have been alive.

Most people buy it hoping clownfish will host, and most captive-raised clownfish will ignore it completely.

It wanders until it finds the right light and flow, and it will sting corals along the way — don't add one to a packed reef and expect it to settle politely.

Condylactis Anemone

Sold constantly as a budget cleaner shrimp, but they're not cleaners — they're scavengers that will pick at soft coral polyps, especially Zoanthids and Mushrooms.

The caution rating undersells the risk; if you have a reef with soft corals, skip these entirely.

In a FOWLR with aggressive feeding they stay occupied with food scraps and do fine.

Camel Shrimp

One of the most striking tubeworms available, and it survives captivity better than many smaller feather duster species.

Current matters a lot — place them where flow reaches the crown but is not blasting directly at it.

They will drop their crown if stressed or grabbed, and it does grow back, but it takes weeks and leaves them vulnerable in the meantime.

Feed phytoplankton twice a week and they will stay expanded and healthy for years.

Giant Feather Duster

Jorunna Nudibranch

The largest clam in the hobby, and it earns every inch of the footprint it eventually takes up.

Unlike smaller Tridacna species, gigas is more light-dependent as a juvenile and needs high-output lighting from the start.

They grow slowly but grow significantly — budget for the space they will need in three to five years, not just today.

Place them on flat open rock or sand; they attach by byssus threads and do not do well being repositioned once settled.

Gigas Clam

Underestimated because they are cheap, but they do real work that more expensive cleaners do not.

They are constant sandbed sifters and will work through fine substrate keeping it turned and oxygenated.

Some are wild-caught and arrive with parasites — quarantine before adding to an established system.

Transparency makes them fascinating to watch, especially after feeding when you can see exactly where the food went.

Ghost Shrimp

Safer around the rock structure than Long Spines and significantly less hazardous to accidentally brush against in the dark.

Good algae grazers that work through film algae on glass and rock without the coralline-grinding behavior of larger urchin species.

Stay small enough for nano and mid-size systems where a Long Spine would exhaust the available grazing area too quickly.

Straightforward care — stable parameters and established algae growth is all they need to sustain themselves.

Short Spine Urchin

Named for the constant rocking display they perform — it is their actual behavior, and it is as distinctive as the name suggests.

They do best in groups and in association with an anemone host, where the colony and behavioral display really show what these animals can do.

Very small and vulnerable to predation — keep them only with peaceful, appropriately sized tankmates that will not view them as a snack.

A dedicated nano built around an anemone and a group of three to five Sexy Shrimp is one of the cleanest concept builds in the hobby.

Sexy Shrimp

Invisible until they start feeding, at which point a forest of white threads suddenly spreads across the sandbed from crevices in the rock — genuinely surprising the first time you see it.

They extend long feeding tentacles to collect detritus and particulate matter, then retract everything back into the tube between feedings.

Completely harmless, impossible to accidentally overfeed, and a reliable indicator that your rock has healthy microfauna living in it.

If you do not have them yet, they will likely show up on their own — most tanks with quality live rock eventually develop a population.

Spaghetti Worm

The gold-banded cousin of the classic Banded Coral Shrimp — same behavior, same cleaning station personality, just rarer and more expensive, which is why collectors seek it.

Like its cousin, it'll set up a territory and interact boldly with fish.

One per tank unless it's a mated pair; they're territorial enough to kill each other if they share space.

Boxing Shrimp

Often overshadowed by Maxima and Crocea, but genuinely the most adaptable Tridacna for a range of lighting conditions.

The fastest-growing tridacnid — they add visible mass over a single growing season under good conditions.

Unlike Maxima, they rest on the substrate without needing to attach to rock, which makes placement significantly more flexible.

Mantle patterns tend toward earthy browns and greens, but high-quality specimens show iridescent blue and gold tones that photograph exceptionally well.

Squamosa Clam

One of the most forgiving anemones in the hobby — Condylactis recover from rough shipping and suboptimal parameters faster than almost anything else.

Clownfish will occasionally explore them but do not host naturally; do not count on a pairing forming the way it does with BTAs.

They wander until they find a spot they like, and that migration can irritate corals in the path.

Good flow, strong light, and regular meaty feedings will get them settled and growing steadily.

Real reef knowledge.
Built together.

Browse by category

Discover

Magician zoanthids

King Kong Yuma mushroom

Elegance coral

Kryptonite candy cane

Exosphere zoanthids

Hologram hammer

Stratosphere zoanthid

Blue Velvet Damselfish

Paccagnella's Dottyback

Orange oxide zoanthids

Real reef knowledge.Built together.

Browse by category

Discover

Magician zoanthids

King Kong Yuma mushroom

Elegance coral

Kryptonite candy cane

Exosphere zoanthids

Hologram hammer

Stratosphere zoanthid

Blue Velvet Damselfish

Paccagnella's Dottyback

Orange oxide zoanthids

Real reef knowledge.
Built together.