New Tank Setup

Contrary to popular belief, goldfish do not live in bowls. The lifespan of a goldfish is 20 years on average, and fancy breeds can grow to 10+ inches, common goldfish can grow to 12 inches.

They grow to the size of their tank in the same way as a kitten will grow to the size of the bottle you put it in. I'm not in the habit of keeping kittens in bottles, so I don't keep fishes in bowls.

So, here are my fishes in their old tank, a 110L.

As the er... gold goldfish Ronnie is growing big, he needs to be in a larger tank, to allow him to swim in a straight line for at least 3 feet.

So, I bought him this:

A 300L tank, at just under 4 feet long.
This should provide him and his tankmates Genghis and Kubla, black ranchus, sufficient space to grow to their maximum potential, and to their maximum lifespan.

The new tank compared to the old tank. We are so getting thrown out of this house.

Now, the crap stuff.

The recommended gravel for goldfish is dorset pea gravel, 3-5mm. Goldfish are bottom diggers, so they'll sift through the stones looking for any food they have missed...this size gravel is too large to swallow, and too small to get stuck in their mouths.
It needs a hell of a lot of rinsing.

It needs to be rinsed until the water runs clear, this took two days of soaking and rinsing. Painful.

End result: two buckets of rinsed gravel.

When putting in gravel, fill the tank some of the way first to cushion the stones.

Gravel in place. Water still a lovely gravelly yellow :/

Filling the rest of the way.

FULL.
I left the water to stand for 24 hours, to remove chlorines, chlorosamines, etc. I then did a 20% water change, adding water conditioner.
Turned the heater on to match the water temp to the old tank (25 degrees).

Now to explain to Ronnie that he's moving...

       Into a 300 litre tank.

The fish move itself:

To establish the bacteria in the new filter, I moved the sponges from the old filter, and crammed them in. This has to be done quickly, to prevent any bacteria die-off.

Also, I syphoned 80 litres out of the new tank, so I could move as much of the old tank water over as possible.

So, the fish were temporarily homed in a plastic storage box, with their old tank water. The filters were removed and crammed in with the new sponges.
The gravel was taken from the old tank, and transferred to the new tank, as the gravel will also hold some of the necessary bacteria. The tank was topped up, temperature checked. and finally, fishes moved across.

Finally, all that's left is to sort out the tank hierarchy.

"SHUT UP!"