As for my dream aquarium, a lot of the animals may be harder to get, but it would have a focus on big and small species throughout the world's water.
Amazonian Adventure
A walkthrough exhibit would first lead to the "Central American Rivers," holding a small group of Strawberry poison dart frogs. A tank would hold a few Midas cichlids, and a Plumed basilisk would live in another terrarium. Farther south, into the "Guyana" section, two 20 gallon tanks holding guppies and bucktooth tetras would be display side by side in a wall. Near those tanks, a large tank holding an Arapaima, Redtail catfish, and some Peacock bass would be visible to guests. Two larger exhibits would hold a green anaconda and a Cuvier's dwarf caiman, while a small terrarium would exhibit a Goliath bird-eating tarantula. The exhibit would then go farther south into the "Orinoco River Drainages," holding a tank for Red-bellied and Black-bellied piranhas, along with another for Cardinal tetras and Hockeystickfish. A small terrarium would hold Blue poison dart frogs. Meanwhile, a large tank will hold Pacus, Matmata turtles, Rosette river stingrays, and Severum. An Electric eel tank would be located nearby. A large exhibit would hold Orinoco crocodiles. In the "Neotropics," a tank would hold Blue tetras, Penguin tetras, Rummynose tetras, and Sterba's corydoras. Nearby are a pair of terrariums, one for Red-eyed tree frogs and one for a Red-tailed boa. Another large exhibit would hold Black caimans and Broad-snouted caimans. Finally, in the "Brazilian Blackwaters," two 30 gallon tanks would exhibit discus in one and Silvertip tetras and Neon tetras in another.
Rivers of the Old World
The exhibit would start in Africa, exhibiting species of Lake Mbuna in Africa - Zebra obliquidens and Mbuna cichlids. Nearby is the Nile, two larger exhibits would hold Hippopotamus and Nile crocodiles. In the Congo, a large terrarium would hold a Nile monitor, while two tanks exhibit Goliath tigerfish and Elephantnose fish and Lake Tangayika cichlids. In a mid-sized exhibit, a Dwarf crocodile or two could swim about or bask on dry land. Finally, in a large aquarium, African manatees would be exhibited. In the Asiatic section soon following the African species, there would be the "Sri Lanka" tank, holding Cherry barbs. The "Himalayan" tank could hold Zebra danios and Leopard danios with another holding Giant danios. The "Myanmar" tank would be home to Burma danios, Redfin danios, Danio choprae, and Celestial pearl danios. In a large pond, koi and goldfish would be exhibited. Meanwhile, in the "Yangtze River" section, a tank could hold White cloud mountain minnows while another terrarium would exhibit a Chinese crocodile lizard. Another tank could exhibit larger fish, like Giant snakehead, Northern snakehead, and Chinese sturgeon, while a fourth exhibit could hold Chinese alligators. Over in the "Mekong Basin," a small Siamese fighting fish tank and a tank for Kissing gourami and Royal knifefish would be cool, as well as a much larger tank for an Asian arowana. In the Queensland section, a small terrarium for Verreaux's frogs and a larger tank for some Queensland lungfish would be exhibited. Finally, a European section would hold an outdoor European otter exhibit.
North American Waterways
In this exhibit, the focus would be on North American rivers, lakes, and coasts, mainly on the east coast. A lake section would hold a tank for Smallmouth bass and Longear sunfish, with another, larger one for Northern pike, Shortnose gar, and Largemouth bass. An exhibit would be made in front of the building for Green-winged teal, and another inside for American alligators. A "Lake Tenotchitlan," exhibit will be made for Axolotls. Meanwhile, in the rivers, a tank for Orangespotted sunfish and Channel catfish will find its home, as well as another for Bull sharks and a large indoor exhibit for Northern river otters. In a Cuban river exhibit, a Cuban crocodile could be exhibited. Finally, we would be in the ocean, on coastal sand flats. An exhibit would display Chain catsharks, with another tank holding Bonnethead sharks, Atlantic tarpon, Cownose rays, and Spanish mackerel. A smaller tank would hold Garfish. Another small tank would hold Cannonball jellyfish, and a large exhibit with one or two pools would hold Atlantic bottlenose dolphins. The seagrass beds would hold a tank for West Indian manatees and Green sea turtles further down the path from the dolphin exhibit, and past that is the Caribbean reef tank, filled with predators such as Green moray eel, Nurse sharks, and Great barracudas, along with Porcupine puffers and Stoplight parrotfish. Finally, the Pelagic section would be reached, holding Green sea turtles, Ocean sunfish, Sand tiger sharks, Blue marlin, mahi mahi, and Atlantic sailfish in a large tank. Another smaller tank would hold Mauve stingers. In another complex of two large pools, Short-beaked common dolphins and Short-finned pilot whales would be present.
Western Waters
This would focus on California's coasts. A sand flat area would hold a Grey smooth hound tank, and a much smaller Purple-striped jellyfish tank. The kelp forest tank would hold Kelp rockfish, Leopard sharks, Garibaldi damselfish, Kelp bass, and other species of kelp-dwelling fish. The Rocky Shore exhibit would be a large, indoor exhibit featuring California sea lions, Harbor seals, and Sea otters.
Pacific Point
This would be the Indian and Pacific Oceans, starting off in Pelagic Hawaii with an outdoor area for Hawaiian spinner dolphins. Farther in, a Pacific reef section would hold multiple tanks, one for Royal angelfish, Ocellaris clownfish, Longnose hawkfish, and Purple queen, one for a Naso Tang, a Longnose butterflyfish, a Fire goby, and a Yellow boxfish, one for a Clark's clownfish colony, one for Grass puffer, Red lionfish, Tomato clownfish, and a Zebra shark, and a small one for Flowerhat jellyfish. Further along is the Australian kelp patches, a small exhibit featuring Leafy sea dragons. The "Jellyfish Lake" exhibit would hold Golden jellyfish, a species found in the Jellyfish Lake in Palau. A shallows section would hold Winghead sharks in a tank and Finless porpoises in another. The estuary would hold Japanese puffer and Mangrove red snapper in one tank, with Saltwater crocodiles in another exhibit. Finally, the Red Sea Reef would hold four tanks, one for Masked butterflyfish, Sohal tang, and Bicolor parrotfish, one for Red Sea Eritrean butterflyfish, Spotfin porcupinefish, and Yellowbar angelfish, one for Emperor angelfish, Red Sea bannerfish, and Humpback red snapper, and one for Blacktip reef sharks, Whitetip reef sharks, and Manta rays.
Mighty Mediterranean
The coastal section would hold shorebirds such as Pied avocets, Eurasian curlews, and Greater flamingoes. A small tank would hold sardines and European flounder. Another larger one would hold Smalltooth sawfish and Thornback rays. Another, similarly sized exhibit would hold European sea sturgeon, and a large, two pool complex would hold Striped dolphins and False killer whales.
Polar Plunge
This would be divided into the tamer versions of the poles, moving farther towards the poles as the exhibit advances. The first exhibit would be for Alaskan reefs, with a small tank exhibiting China rockfish and Black scraper. Another small tank would hold Fried egg jellyfish and Cross jellyfish. A larger exhibit holds White sturgeon, and a massive pool holds Pacific white-sided dolphins. In the Northeast Pacific Deep Sea section, a tank would hold Granrojo and Deepwater trachymedusae. Another holds Spotted ratfish, Venus's flower baskets, and Demon stingers (Stonefish). A third holds Fanfins, Footballfish, and Yeti crabs. In the Icelandic Rocky Coast exhibit, puffins nest on a large beach. In the Arctic, an Arctic cod tank is available to view, as well as another similarly sized aquarium for Lion's mane jellyfish. Exhibits would also hold Ribbon seals, Walrus, Polar bears, and Belugas. In the South African Beaches section, a colony of African penguins would reside. A colony of Southern rockhopper penguins and a couple of Commerson's dolphins could make their home in a "Strait of Magellan" exhibit. Finally, in the Antarctic area, exhibits for Crabeater seals, Brown fur seals, and Adelie penguins and Emperor penguins would be visible to guests.
Reptile House
This would just hold a variety of reptiles not exhibited elsewhere in the zoo. A European woodlands exhibit would mimic the Hermann's tortoise's natural habitat. A Ring-necked spitting cobra, African spurred tortoise, Aldabra tortoise, Jackson's chameleon, Giant leaf-tailed gecko, and Panther chameleon could reside in exhibits throughout the African section. A tuatara and frilled lizard could share a space in the Australian Outback, with another holding an Inland taipan. A larger terrarium could hold a Perentie lizard. Meanwhile, on New Caledonia, a New Caledonian giant gecko would be visible to guests. Marine iguanas would be exhibited on a rocky Galapagos Shore exhibit. Two more larger exhibits for an Indian cobra and several False gharials would finish off the aquarium.
Sorry I rambled, I tend to do that, I just love this and I'm currently making it in Zoo Tycoon 2, only getting the easier to buy animals first, then working my way up to larger animals like dolphins, polar bears, and hippopotamus.