This is place of peace and quiet for pink (peach, salmon-colored) anemone, likely Cerianthus orientalis.



Environment in the 90g was unsuitable for it (too high flow, wrong pattern, aiptasia and sometimes red cyano after feeding non-photosynthetic corals. In own tank it is much better.

Tank setup:
Nano Cube 12g, with back chambers cut away,
Stock light, 24W 50-50 PC, usually only moonlights at night are used
Current USA Subcurrent internal filter/ surface skimmer (analog of Tunze device), with double LockLine output, allowing set uplifting and reflected low. AquaClear or any other HOB filter was unsuitable.
50W heater with heater protecting plastic grid (Hydor),
grounding probe
Tahitian Moon black DSB, unused by anemone, well with Direct Ocean normal sand, also not used,some LR (CaribSea Reef Rock, with established bacterial population)
Few sand sifting mini-snails,1/2".
Water: any salt mix I have at hand, IO, Reef Crystals, Red Sea, Red Sea Pro, Kent, Oceanic. SG 1.026, 77-79F, alk 9-10 dKH, weekly water changes, clean tank.
It's all.
Note, that I'm keeping this tank for months, not for years. Anemone is 1 yr old.
Add yours, if you keep tube anemones too.

Positive sides:
After initial setup, what could be pain in the neck with finding proper pattern of flow and suitable burrowing media (mine preferred rock-glass on the sided), this is a very low maintenance, no surprises, high visual impact tank. Anemone fills practically all the tank, ~17" maximal diameter, alien creature in combo PC light. As they say, best bang for your buck - one $54 anemone, not tens of corals with the same price each. Low energy consumption. Good night time observations tank, when moonlights are on. Draws attention, when enter the room.

Negative sides:
High risk to make a mistake, when evaluating size of anemone in LFS. Mine looked 3" in diameter, when open, and it became 2.5x larger the same day in home tank. Needless to say I had to change aquascaping to free space for it, it wasn't in my plans.
It seems that it grows. 11" maximum diameter in the beginning, now ~17" (tank is ~16", if it continue to grow, it will need the bigger tank, likely hexagon).
It closes in bright light or whatever it finds it suitable. But it still open most of the time.
Sensitive to flow pattern and toxins, produced by other living organisms, in the water. Not dies, but closes, until situation improves.

Feeding:
Usual for tube anemone, small shavings of the meaty seafood, mysis, Plankton, thin pieces of krill once in two days or so.

Particularities:
It seems to be photosensitive, and moonlight should be right above its center, or tube anemone changes position. Built- in moonlights in NC are not in the center, had to unscrew and move lid for a time being.

Tahitian Moon black sand wasn't accepted or used for building a tube, Ocean Direct live sand was better.

very interesting... can you post some daylight pics? This tank looks cool.

The first one is daylight picture, under combo PC (50% actinics, 50% 10,000K).
More, the same light:

My camera is point-and-shot, could be better - the actual color is more intense.

This is under sunlight, before I added DSB:

Here it was in 90g tank, in betta bowl with DSB:

Compare to chromis size

very cool

awesome tank and anemone... do you have problems whit the anemone?

Nice! That 90g is awesome too!

Thanks! Especially for 90g evaluation: I'm more accustomed to get wrist slapped for not cleaning coraline algae frequently enough, not having clean white sand, not aesthetically mounted corals, brighter light (this one had ~1W/gal, 24"D) and so on
BTW, if you want to see the properly looking BIG tanks for tube anemone, take a look here and here.

Troubles with anemone, past and present, in order of importance for me. For anemone it was simply not proper environment.

Past, in 90g:
1. Too big.
I estimated it 3" in diameter, and had that space for it:


Flow is sufficiently low only in the left and right corners, under powerhead, moving water to the overflow at the opposite side, and under overflow itself. Had to empty quarter or third of the tank for anemone, that made tank looking incomplete:

Considered giving it personal hex tank and add other tube anemones (neon-green center and purple tentacles) and and in ideal case have 3-4 tube anemones of the same kind, maybe they will reproduce.
But always something else comes first.

2. It has certain preferences for a flow (tentacles, extended free in the flow, but nor swept away or tangled). After adding dendronephthya, that requires very high flow and changing flow pattern for it (BTW, is it happening all the time with me only, acquiring new livestock, and later facing undescribed incompatibility with the old one, and changing all again and again to make environment suitable for both, old and new?). Tube anemone left its place in search of peace, had to return it back and restore previous pattern of flow. It is difficult to do, if anemone stuck behind the rockwork.

3. Almost continued feeding for dendronephthya and growing sun corals collection increased bioload, periodically tank had red cyano, bristle worms swarmed everywhere, including at the base of tube anemone. It didn't like it, and stayed closed, until situation become better. Aiptasia started to grow fast. Massive aiptasia treatments every 3 weeks also affected water quality.
Tube anemone is sensitive to such things, and I couldn't reduce feedings for NPS corals. Now in own tank with clean water, no bristle worms and aiptasia or red cyano, it finally found peace.

4. Valentini puffer likely tried to taste tube anemone and got pale "burns"(?) on the face for 1.5 days, then they disappeared. No signs of significant suffering.
Other fish in the tank had no problems: chromises, percula clown, damsel, lionfish.

5. My tanks are bare bottom, tube anemone is described requiring deep sand bed (later found that in few cased they chose live between the rock). I tried usual substitutes: tube, betta bowl and glass, filled with finest sand (CaribSea Ocean Direct). Mine tube anemone changed its position in the vessel frequently, is it species specific - can't say, others had other kinds of tube anemones in the tubes without problems. Bowl gave more space to move, and space to hide from flow: between the rim and a sand.

6. Being sucked by powerhead.
In the first leave, tube anemone was sucked into 600 gph Seio 620. Was found in the morning, freed, put in high glass vessel (coffeemaker jar). Restored appearance and formed new tube quite fast, withing a month or so.

7. It was bought tubeless. It was positioned so in LFS, that it was impossible to see the tube. Tube was connected to it, and had something like green puss. A.Thiel website has description how to insert anemone back, but I never managed to do that. Severed connection, without disinfecting it and used new live sand from the bag (Ocean Direct, I mean). It formed tube quite soon.

8. Leaving tube and forming new tube. Don't flame me, I did my best: tube anemone left its tube 3 or 4 times during one year and grew tube back. Once - in NC 12 - without using sand at all. Pictures are here.

9. Staying closed for a prolonged time, then water quality was not good (see red slime and killing aiptasia above, add drastic changes in alkalinity: below 6 dKH and above 15 dKH). Correcting problem allowed it open again.

In Nano Cube:

1. 12g Nano Cube is too small, 24g is not mailable and costs an arm and a leg locally.
Hexagon seems to be the only viable option in future.

2. HOB filter and skimmer create improper pattern of flow, luckily I had Subcurrent internal filter/surface skimmer. Tunze makes similar, but more expensive product.

3. Heater guard (Hydor brand, readily available), to prevent contact of tentacles with hot object.
Grounding probe - just in case.

4. Tahitian Moon black sand looks good, but is not used by tube anemone. No noticeable ill effect too, just wash well at beginning. But fine calcareous sand will be better.

5. Moonlight in NC is positioned not in the center, and light should be above the anemone mouth, or it will orient itself as sunflower. Had to move lid aside.

6. Do not forget to feed, preferably once it two days, very little, to keep it interested coming out from tube.

It's all.
If you keep tube anemone(s) in nano, add your information.