Author's Note - Written originally for Wattpad Sc-Fi's Europa challenge - Word Limit between 2 and 4 pages. I took it down for awhile as it is now available as part of  the"Star Clash" anthology on Amazon. As the book is available for free, I thought I'd repost the story as part of  ProjectRefresh's November  2016 outerspace challenge

(Author's Note - The prompt for this story was Europa, one of the larger moons of Jupiter. Europa's surface is mainly water ice. The red lines criss-crossing the surface are deposits of magnesium sulphide. Many Earth scientists believe there may be an ocean of water or slushy ice beneath the surface, and if so, Europa may be the other place most likely to support life in our solar system.)

Vik swam through the dense patch of water, sampling the rich cocktail of phyllosilicates as he sped through. He could feel the heavy slipperiness of it on his skin, as well as the spicy taste of it in his mouth. Delicious.

If he hadn't been chasing his pod brother, he would have lingered to eat his fill. As it was, he filed the location away in his memory. It was halfway through Slow Tide, perhaps he would have time to come back later and find this patch again.

Pol was only just ahead of him, a shining blue in his sonar-ray vision. Vik forgot about the food and darted after Pol, he would catch him this time, he was certain.

He swerved to the left as his sonar detected a rocky outcrop in his path, then back to the right to avoid a car being driven by an idiot with more status than brains. Vik swore silently. Why couldn't the idiot swim like he was meant to? Why did he think he'd been born with fins? Sure cars could move faster, but they also guzzled the magnesium and churned it out the other end as waste. Not to mention encouraging the driver to become fat and lazy.

Another click further and they reached the outskirts of the city. Vik glanced up at the huge circular buildings floating above them, checking for other traffic, before following close on Pol's tail. He skimmed past the thick metal cable which anchored the central sphere of the city to the top of the mountain. The tether allowed the city to move fractionally with the tides, without being swept halfway around the planet every day.

Vik knew there were creatures who spent most of their lives on the plains at the bottom of the sea, but he couldn't imagine living so far down—the pressure would have to be intense. Not to mention hot. Life on the sea bed required significant adaptations to the environment. On the whole, the bottom dwellers he had seen tended to be quite small, with thick skins and numerous appendages. Not to be rude, but honestly, some of them looked pretty creepy.

Personally, he liked living up near the ice. Most of his people did.

Vik looked up, just in time to see Pol flicking his tail in triumph. While he had been distracted, Pol had reached the goal of the Pod Brother's Twelfth House. Vik could just imagine the smirk on his face. Soon, he promised himself, soon he would be fully grown and then he would win their races.

Inside the Pod House, Pol extruded an appendage so he could grab himself a bottle of Phizz and guzzled it with evident enjoyment.

"Want one?" he asked. "Or did you fill up on the raw stuff?" He gave a condescending smile.

"I like it raw," Vik said defensively. "Besides, it's much more healthy than that processed muck you drink!"

"Careful! You're starting to sound like old Maz, always wanting to go back to the 'good old days' before we had modern technology."

Vik knew Pol considered him weird, even primitive, for preferring wild food, but as far as he was concerned it had so much more flavour. Not to mention it was free. Bottled Phizz cost money and there was no way he was going to pay for something that he could find for himself with a bit of effort.

"Well it was good enough for our ancestors for the last million years! It should be good enough for us."

"There! I told you, you sound just like Maz!"

Before they could get into an argument, two females poked their heads inside the entrance. "Hullo, anyone there? Oh, hi Pol, hi Vik. Fast Tide's going to be a big one this time. We're going to ride it—want to come too?"

"When are you going?" asked Pol.

Automatically, Cal consulted the neural locator in her brain that allowed her, and indeed everyone on Kaia, to know exactly what the Tides were doing. There were two Tides in every cycle, Slow and Fast, each building up to a peak and then declining, as Kaia circled Mana, the huge giant gas world next to them. Scientists, like Maz, said that the tides were what kept the sea from freezing solid like the ice roof above them.

"About two hours before it peaks. That should give us enough time to reach empty water, away from any obstructions."

"That sounds fun! We'll meet you outside your House." Pol answered for both of them.

"Great!" said Cal. "Catch you then!" She shot off with a flick of her tail, followed swiftly by her pod sister, Jai.

"I wouldn't say 'no' to that!" smirked Pol, once he was sure she was out of earshot.

"In your dreams!" said Vik.

The next Tide found Pol and Vik outside the Pod Sisters' Ninth House. Cal and Jai were ready and led the way, all four darting between the buildings in single file until they were clear of the city. Then they moved smoothly into formation, taking turns to lead and allow the others to save their strength in the slipstream. Soon, they were travelling at high speed, forty clicks or more, revelling in their youth and power.

Who needs a car? thought Vik, enjoying himself. Why would anybody want to be stuffed inside a container, when they could be doing this with their own bodies?

The Tide was nearing its peak and all four felt the push as they raced with it, diving and twisting at speeds now approaching a hundred clicks. Vik could hear high pitched whistles of excitement coming from all four of them. What could be better than this?

All too soon it was over and time to swim home against the tide.

The return journey took much longer, but it had been worth it, thought Vik. As they approached the city, he could taste the change in the water.

"You have to admit, the water tastes different here," he said to Pol. "Not as clean and fresh as out there."

"It's not so bad," answered Pol.

"My Mother says we should consider putting a limit on the number of cars and even houses," put in Cal, unexpectedly. "She says the construction process alone generates more waste than we can manage, not to mention what's produced every time a car is used."

"I've heard the magnesium sulphate levels are rising everywhere," added Jai.

"Perhaps," said Pol, struggling to be polite. "If it is, we'll just have to deal with it—you can't fight progress, you know."

They said goodbye to the females at their House and continued on to their own.

"I didn't want to be rude about Cal's Mother, but that's all crap!" said Pol. "Lies spread by a few scaremongers who are frightened of progress."

"Maz says the same thing and I wouldn't call him a 'scaremonger.' A lot of what he says makes sense, Pol. After all, we don't know what the long term effects will be of all the waste being produced."

"But the planet is huge! There are millions of cubic clicks of water—you can't tell me a little bit of magnesium sulphate is going to make a difference to that."

"That's where you are wrong. You don't work in Waste Management like I do, you haven't seen the quantities we deal with. We're funnelling as much of it up to the top of the Roof as we can, but no-one can be sure whether it will stay there for ever. Sonar-ray scans show there are now huge patches of magnesium sulphate covering the Roof—it's even filling the tidal fractures. Maybe one day it will leak back down. Maybe it's already started."

"You worry too much, Vik. There are clicks of ice between us and the top of the Roof—and if it does start leaking back down, we'll deal with it. We have cities now all over the planet, research centres, laboratories, there's even talk of exploring the rest of this star system!" Vik could hear the wonder in Pol's voice.

Vik didn't understand it. "What on Kaia for? All the other worlds are dry rocks—or made of gas like Mana."

"Not all of them. I've heard the third one from the star has water. Water actually on the surface, with no ice or Roof. Can you imagine?"

"That's just silly!" scoffed Vik. "How would the water stay on without a Roof to cover it?"

"We don't know yet, not for certain. There's one theory which says there is a layer of gas over the top, holding it down. Another, that there is some sort of magnetic field. It's fascinating."

"For some!"

"In any case, it's good to know there is another source of water in the system, just in case the worst does happen and we need more."

"What if there are people already living there?" teased Vik.

"Now who's being silly? Everyone knows it's way too hot, nothing could live under those conditions. Though some scientists think it's possible there might be something microscopic. We'll have to wait and see. Wouldn't that be wonderful, if there was?"