elhazar:

Fish are not cuddly, they do not have soft fur nor do they have cute, sad or otherwise expressive faces. Yet they are living, intelligent and deserve respect as well as proper care: Learn about the Nitrogen Cycle and cycling!

The Nitrogen Cycle

Fish and other aquatic animals as well as rotting organic matter produce deadly ammonia: If allowed to accumulate, they will literally shit themselves to death, quickly. However, beneficial bacteria transform that toxic ammonia into toxic nitrite into mostly harmless nitrate. In aquariums, the accumulated nitrate is removed with water changes. So before you can get any stock, you need to cycle your tank, to grow your colony of beneficial bacteria. However, they do not appear from alone, but you rather need to feed an unstocked and filtered tank ammonia, for example from decaying fishfood, to grow them. After about a month of doing so, you will need to confirm your bacteria colony on your filter media can transform all ammonia without leftovers into nitrate, only then your tank is safe for fish!

Also, goldfish, even the cheap ones you see as feeders and the carnival-prize ones, get to almost a foot long and need a massive tank. Fancy goldfish need at least a 30 gallon tank. Bettas should never be kept in anything under 5 gallons and need a heater. 

Do your research before you get any animal, even a cheap one.

What animals, if any, do you think would survive in a post apocalyptic wasteland? For example a nuclear apocalypse?

drferox:

(Psst. I actually wrote a novel about talking animals in a post apocalyptic scenario…)

The question is going to be ‘how nuclear’ was that apocalypse? Because nature is tough and versatile and an organism only needs to survive long enough to reproduce once in order for the population to survive.

Even around damaged nuclear reactors, most species come back over time. If it is a completely desolate wasteland to the extent that the plants have all died, then not much at all is likely to live there if there’s no food supply.

I’d put money on everything that lives around deepsea thermal vents doing just fine. If the Earth’s geothermal activity continues as normal, the planet doesn’t freeze solid, and significant levels of toxin or radiation don’t make their way down to the thermal vents, they’d keep going just fine. A lot of the miscellaneous deepsea life-forms wouldn’t do so well, though, most of the things across the seafloor feed mainly on dead things that drift down from above.