City Aquarium

City Aquarium

The **City Aquarium** is an aquarium owned by Finn Thresher. The tanks, made of glass and cleaned every night, show the underwater world that is usually so hidden from mortal eyes, the wonders of them on display for all. The scales on the fish sparkle and dance, flashes of rainbows combined with dancing ones on the walls where the glass refracts the light. It is a place meant to reveal secrets, offer new perspectives and inspire joy to any and all receptive to it. The proprietor is always willing to give a tour to any interested parties.

## Main Exhibits

In this space, everyone, regardless of income, can experience the wonders of the sea. It has a number of exhibits, all of them meticulously cared for and every resident within healthy and thriving. Marine animals are frequently vibrant for different reasons than land animals. Their environment is full of flashes of light, catching the top of the water. Shiny scales mimic that tendency. They also seem to see far differently, the corals, for example, look completely different under a strong blue light. If creatures see those colors all the time, it would certainly change the priorities for survival.

### Nudibranch hall

The **nudibranch hall** is a riot of color. Inside reside the thieving *Aeolida*, who eat jellyfish and anemones to steal their stinging cell organelles, others reuse compounds from the sponges they eat, still others produce toxins on their own, or release acidic mucus into the faces of their predators. They don't see much, but they can talk, and some, such as Bundi, are positively chatty.

### Shark tank

Inside the largest of the **shark tanks** houses the specimens that make men reflect on their hubris in thinking they could ever be the masters of the sea, not when so many teeth lurk below. The City Aquarium is unusual in its capability to keep a few pelagic sharks in its shark tank, though there are some other sharks that are there for temporary housing only. There are two lemon sharks that enjoy swimming along the bottom of the tank, a sandbar and bull shark that keep a reasonable truce in the middle, and a tiger shark whose fin slices through the surface of the water. They are fed on Mondays and their curiosity is unusually well-sated.

There are also a number of smaller specimens near the rays in their touch tank. The swell shark, secretly fluorescing without mortal knowledge for another century, a large shoal of leopard sharks, and a zebra shark

### Cephalopods

**Cephalopods** are a class that includes squid, octopus, cuttlefish, and nautilus. These invertebrates are fiercely intelligent, with well-developed senses and large brains. They can solve puzzles and are generally social creatures.

There are small octopus, housed by themselves, such as the blue-ringed octopus and of course, Oscar, a coconut octopus. One of the tanks has a veritable shoal of bigfin reef squid - they are one of the few social species. Another has a flamboyant cuttlefish, as poisonous as the blue ring is venomous.

If one is looking very carefully, one may spot a creature that has yet to be discovered. The mimic octopus is very good at hiding from mortal eyes - it won't be described until 1998, or named in the Linnean system in 2005. But there is no way that Finnegan Thresher doesn't have a way to keep around a creature that everyone agrees is a true wonder of the sea - *Thaumoctopus mimicus* - the mimic octopus.

### Other displays

There are harbor seals and sea otters in bigger tanks, separate from the fish.

Others exist in small tanks, such as the green mandarin. These little friends are from the Ryukyu Islands. They're vivid specimens, greens, blues, and oranges swirling across a small 2-inch body. Though the fist don't swim particularly well, they hop like they're walking on their fins. They do love copepods though. Difficult, but the systems are large enough to house plenty of the food they prefer. Much easier than the sharks, certainly. The male dorsal fin is much larger than the females. There's only one or two to a tank because they are relatively solitary creatures. The males cannot abide each other. They bite quite aggressively.

In any number of tanks are marine vegetation - seaweeds, sea grasses, and algae, depending on the occupants within. Plants are very durable in one sense, they're not picky about their attachment point because of its composition, more its location. Light for photosynthesis filters out relatively quickly with depth, which is why many of the deeper plants are redder in color. And some of the supposed plants are really animals. Like that anemone. It's actually a foot attached to a mouth, and it will eat what it catches.

Much like anemones, corals are animals, not plants. They're even what could be considered carnivores, eating small creatures from the water around them. This makes flow incredibly important, carrying their meals to them. It still has a skeleton, of a sort, all latticed together for it's polyps to extend from. It has lovely coloration, varying from white to pale lavender. The skeleton still has *calcite,* and limestone is nothing more than calcium carbonate. Similar, but not the same. Their skeleton is much like our noses, versus our bones. Structured, strong-ish, but not more than that. Any harder bits are called sclerites, and they're to deter predators, like that angelfish from earlier. Others, like the leather coral, are actually capable of stinging prey and neighboring corals, although their true defense is the toxins they exude into the water column, killing any competition for food sources. Generally, Finn keeps them apart - he doesn't like to encourage active warfare in his tanks.

Then there are what is known as a Large Polyp Stony coral or an LPS. It has a hard skeleton still, but it not a traditional coral. It is also completely carnivorous. This creature doesn't like light, instead using tentacles to catch tiny creatures and bring them into the mouth of each polyp, with a centralized digestive tract. Think the Hundred Handed ones of olden myths, but with more mouths. It can reproduce both sexually and asexually, depending on the conditions it's exposed to. It even comes in black - if you can find one to take home. They don't *need* light, but the organisms they eat *do.* So typically they are found in the shallower seas, attached to old shipwrecks, little overhangs, and caves.

Acanthastreas are a cup coral, but it flattens as it grows, covering rocks and other corals. Which, if they aren't dead when the acan starts, certainly are when they finish. People think of reefs as tranquil places, but these reef builders are in constant competition, stinging each other, releasing toxins, and so on. Their flesh expands and contracts based on external stimuli, and the whole calcium-based skeleton is covered with it, in varying colors, some dull, some bright, some only flashy under that new, ultraviolet light. They can grow as deep as 50 meters down, because even though it can photosynthesize, it also has spiny *teeth*, known as septa, for breaking down whatever it can fit in it's mouth, inside the skeleton along the tract to the organism's body. It's why we keep this magnifying glass in the display, with an old skeleton.

Black Corals are quite rare and not for hobbyists at the moment, but you are welcome to enjoy them here whenever you like. Black corals get their name for the color of their skeletons and are distinguishable for their flexibility and the fact that they must have excellent water quality - particulates are quite damaging for them. The skeleton is lined with spines, and the polyps come in rather stunning yellows, reds, and whites. They prefer to live below 50 meters, but some can be found above. The individual polyps have male or female sex characteristics, but like nudibranches, the entire organism is hermaphroditic. Their softness allows them to take advantage of the currents for their next meal.

There are also starfish, typically with 5 arms, but they can have up to 40, and they can replace any missing limbs should one be consumed by a predator. The Northern Pacific Starfish prefers colder, shallower seas has distinctive upturned arms. Though the creatures may *seem* sluggish, they are quite voracious predators, eating bivalves without mercy, prying them open to feast, doing so by opening their mouths and extruding their stomachs onto their prey, which is then externally digested. Once done, they retract their stomach back inside their bodies. Plenty of things eat them in return, birds, otters, other starfish.

 * Finn's office
* A green mandarin
* An anemone
* A sun coral
* Acanthrastreas are often brightly colored and *hungry*
* A royal angelfish
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## Associated NPCs

* **Barney (the Curious One), Casey (the Affectionate One), and Hogan (the Shy One)** are the harbor seals at the City Aquarium.
* **Chelona** is a sea turtle in the largest tank.
* **Tango, Nemo** are two of the ten otters at the City Aquarium.

#### Bunzi

   **Bunzi** is the nudibranch who will chat with you, if you know what to listen for. Two species are *very* talkative. One Professor Grant described his specimens' chatter as 'the clink of a steel wire on the side of the jar, more frequent when they move, repeated at intervals, and non-existent during apparent sleep.' Furthermore, he reported hearing these sounds from up to 12 feet away from his tank, in conjunction with watching their mouths open and close. One specimen in question was the delightful *Dendronotus frondosus*, over there. It has something to say, whether that thing is food, or calling a mate, or simply enjoying the vibrations in it's body. After all, there are plenty of people that love the sound of their own voice, and while admittedly we may question whether that has meaning for *us,* it certainly does for *them.*

#### Oscar

   **Oscar** is a Coconut Octopus who helps fundraise for the Aquarium. He uses coconut shells as helmets and seashells as shields to hide from predators. He's not especially large and he is very good at using tools.

### NPC Gallery

* Bunzi the Nudibranch
* Oscar the Coconut Octopus
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## References

1. ↑ Smithsonian - A Collage of Nudibranch Colors https://ocean.si.edu/ocean-life/invertebrates/collage-nudibranch-colors
2. ↑ Wikipedia - Nudibranch https://en.wikipedia.org/wiki/Nudibranch
3. ↑ Natural History Museum - Psychedelic Thieves of the Sea https://www.nhm.ac.uk/discover/nudibranchs-psychedelic-thieves-of-the-sea.html
4. ↑ Edmunds, M. *Acid Secretion in Some Species of Doridacea (Mollusca, Nudibranchian)* https://archive.ph/20130415132743/http://mollus.oxfordjournals.org/content/38/2/121.extract
5. ↑ P.H. Gosse, *Evenings at the Microscope*, 1884 edition, p.57 https://archive.org/details/eveningsatmicros00goss/page/56/mode/2up?view=theater&q=Professor+Grant
6. ↑ Wikipedia - Sharks in captivity
7. ↑ Wikipedia - Lemon shark https://en.wikipedia.org/wiki/Lemon\_shark
8. ↑ Wikipedia - Bull shark https://en.wikipedia.org/wiki/Bull\_shark
9. ↑ Wikipedia - Sandbar shark https://en.wikipedia.org/wiki/Sandbar\_shark
10. ↑ Wikipedia - Tiger shark https://en.wikipedia.org/wiki/Tiger\_shark
11. ↑ Wikipedia - Swell shark https://en.wikipedia.org/wiki/Swell\_shark
12. ↑ Wikipedia - Leopard shark https://en.wikipedia.org/wiki/Leopard\_shark
13. ↑ Wikipedia - Zebra shark https://en.wikipedia.org/wiki/Zebra\_shark
14. ↑ Wikipedia - Greater blue-ringed octopus https://en.wikipedia.org/wiki/Greater\_blue-ringed\_octopus
15. ↑ Coconut Octopus - Interesting Facts https://octolab.tv/species/coconut-octopus/
16. ↑ Wikipedia - Bigfin reef squid https://en.wikipedia.org/wiki/Bigfin\_reef\_squid
17. ↑ Wikipedia - Flamboyant cuttlefish https://en.wikipedia.org/wiki/Metasepia\_pfefferi
18. ↑ American Museum of Natural History - the Talented Mimic Octopus https://www.amnh.org/explore/news-blogs/on-exhibit-posts/the-talented-mimic-octopus
19. ↑ Wikipedia - Mimic octopus.
20. ↑ Wikipedia - *Synchiropus splendidus* https://en.wikipedia.org/wiki/Synchiropus\_splendidus
21. ↑ Wikipedia - Sea anemone https://en.wikipedia.org/wiki/Sea\_anemone
22. ↑ Wikipedia - Coral https://en.wikipedia.org/wiki/Coral
23. ↑ Wikipedia - Black coral https://en.wikipedia.org/wiki/Black\_coral