Tubbs Blue

Tubbs Blue is one of the oldest named blue zoanthids in the hobby. The Reef Farm, which still grows it, notes the name goes back at least twenty years. That longevity matters because true blue has always been the rarest colour in zoanthids: most "blue" morphs read grey, silver, or washed-out violet under ordinary tank light. Tubbs Blue built its reputation on holding a solid, rich blue across the whole polyp — disc and skirt in the same deep blue family, with a contrasting mouth — in tanks where other blues faded.

The name itself needs a spelling note for buyers. Listings split between "Tubbs Blue" and "Tubs Blue," sometimes within the same shop: one current vendor titles the coral Tubbs Blue while its own product URL shortens it to Tubs Blue. Both spellings refer to the same morph, and this entry carries both so a search under either spelling lands here. The same Tubbs name also sits on two Montipora in this database — Tubbs Blue Digitata and Tubbs Stellata — which are stony corals from the same era of named pieces. They share a name lineage and nothing else; this entry is the soft-coral zoanthid.

One vendor files the morph under the scientific name Zoanthus danae, while others list it plainly as Zoanthus sp. Hobby zoanthids are almost never verified to species, and this entry follows the cautious label while recording the danae filing here. For care and identification purposes the distinction changes nothing: a small-polyp colonial zoanthid that spreads as a mat over rock and rubble.

The colour behaviour under light is the trait keepers talk about most, and it runs opposite to several other blue zoas. In a long-running Reef Central discussion from the metal-halide era, keepers reported that Tubs Blue turned more blue as light intensity increased, while the skirt shifted toward a lighter brown, and that a separate morph sold as True Blues behaved the other way — dark blue in shade, silvery under bright light. One keeper in that thread called Tubs the only blue zoanthid he had owned that could sit right under the lighting and keep its blue without turning grey. Modern LED-era vendor guidance is more conservative: start a new frag in lower light and raise exposure gradually over two to three weeks, within a 75 to 150 PAR working range. Both accounts can guide a new colony — acclimate slowly, then judge by colour: a settled Tubbs Blue that is holding deep blue and staying open has found its light.

A second colour note comes from The Reef Farm and is worth knowing before judging the coral under an evening blue-heavy schedule. In their description, this morph does little to impress under blue lighting, and then grabs the eye from across the room when the whites come on and many other corals look flat. Most collector zoanthids are sold on their actinic glow; Tubbs Blue earns its place in daylight spectrum. A buyer comparing frag photos should ask what spectrum the photo was taken under, because this morph photographs closer to its real daylight colour than most.

Flow should be moderate and indirect: enough movement to keep detritus from settling on the mat and to keep polyps clean, with no pump aimed straight at the colony. The coral is photosynthetic and needs no feeding. Vendor guidance read for this morph notes that fine-particle plankton blends and similar foods, offered a few times a week with flow paused, can support colour and growth for keepers who choose to feed — an optional extra, never a requirement.

Reef To Go's standard reef parameters suit it: 77–79°F, salinity near 35 ppt (about 1.024–1.026), alkalinity 8–10 dKH, calcium 400–450 ppm, with low but detectable nitrate and phosphate. Vendor ranges read for this morph run a little wider — nitrate 5–15 ppm and phosphate under 0.10 ppm on one page — and zoanthids have no calcium skeleton, so there is no dosing demand from this coral itself. Stability matters more than any single number, and The Reef Farm's "touchy from time to time" warning usually traces back to swings rather than to a parameter sitting slightly off target.

As a mat-forming zoanthid it will spread over whatever rock it can reach. Give it a defined rock or island with room to grow, and keep that spread in mind before placing it against the main rockwork, where a healthy colony can overrun slower neighbours over time. It carries the mild sting typical of zoanthids, so direct contact with delicate corals is still worth avoiding even though it harms little by reach alone.

Safety applies to this coral as it does to zoanthids generally. Some zoanthids and their Palythoa relatives can carry palytoxin, and there is no visual way to tell which colonies do. Handle and frag with gloves and eye protection, keep the coral away from open cuts, handle it submerged where practical, wash thoroughly afterwards, and never boil, steam, or pressure-wash rock that carries it, because heat can aerosolize the toxin. Handled with that respect, a settled colony is a durable, long-lived aquarium coral.

Field notes — what keepers report

- Difficulty reports split, and both sides belong in the record. Saltwaterfish.com rates its aquacultured Tubbs Blue Easy, with moderate light, moderate flow, and bottom-to-middle placement, and a hobby roundup lists Tubbs Blue among the easiest zoanthids to keep and a good beginner choice. The Reef Farm takes the other side: Moderate care level, a warning against treating it as a great beginner zoa, and the observation that even after twenty-plus years in cultivation it still has a tendency to be touchy from time to time. The entry above follows the farm's rating, because a morph that sulks at parameter swings will disappoint a keeper who bought it on an Easy label.

- The light-and-colour reports from the metal-halide era are the most specific keeper accounts found for this morph. In the Reef Central zoanthid photo thread read for this dossier, keepers reported Tubs Blue gaining blue intensity as light increased (with the skirt lightening toward brown), contrasted it with True Blues going silvery in bright light and staying dark in shade, and singled Tubs out as the one blue that held its colour directly under halides without greying. Those reports predate modern LEDs, so they describe a tendency rather than a PAR prescription — the current vendor range of 75–150 PAR with a slow 2–3 week acclimation remains the safer starting plan.

- Spectrum changes the verdict on this coral more than on most zoanthids, per The Reef Farm's grower notes: unimpressive under blue light, eye-catching under whites when neighbouring corals look washed out. Keepers running blue-heavy evening schedules may underrate a healthy colony; check it under the daytime spectrum before deciding it has lost colour.

- The two spellings cause real confusion in listings. Top Shelf Aquatics sells "Tubbs Blue" (current listings at $39.99, and $44.99 for an almost-WYSIWYG frag); Saltwaterfish.com titles its aquacultured frag "Tubbs Blue" while the product URL and slug use "Tubs Blue," priced at $21.99 on sale from $36.99 at the time read; The Reef Farm lists "Tubbs Blue" as a 6–7 polyp frag, out of stock when read. Same morph throughout — price and polyp count explain the spread, and no verified historic peak price was found in the sources read, so none is claimed here.

- A keeper in a 2009 Reef Central thread reported keeping two kinds of "tubs blue," both in the bottom third of the tank and looking great while a prized Purple People Eater in the same system was going dull — a small, dated data point, offered here as placement anecdote rather than guidance: bottom-third placement under strong halides worked for that keeper.

- Pest and decline notes in the sources read are family-level rather than Tubbs Blue-specific: zoa-eating nudibranchs and spiders found on inspection and dipping, filamentous algae smothering polyps, and detritus left sitting on the mat. No Tubbs Blue-specific melt rate or cure was found in the sources read, so this entry claims none. Dip and inspect new frags, baste detritus off the mat, and keep parameters stable before reaching for treatments.