What's key for happy goldfish?

Hey everybody, I'd like to start by saying this is my first time on the site, it's nice to find a group of like minded people searching for more practical and safe means of living.

So I just started my first aquaponics system on a small scale. I'm currently using a 275 Gallon IBC container in a flood and drain system. Everything seems to be going well. I'd like to use tilapia in the system soon but it's stocked with goldfish at the moment because they were a cheaper alternative.

So my question to you guys is, what can I do to keep my goldfish happy? I know it seems like a trivial question but I've never owned goldfish and I want to make the best environment possible for them.

What types of submerged plants do they like and feed on?
Are goldfish omnivores? If so will they eat meal worms?
Is it okay to use pea gravel in the bottom of my fish tank?
Do goldfish like having places to hide?

I've already covered the necessities for their survival, the tank is getting plenty of aeration, the water temp. stays between 60-80F, I'm feeding them twice a day without overfeeding, plenty of sunlight.

If possible could you guys post some pictures of your goldfish tanks it would be much appreciated, thanks for any help and advice

Jason McF: Have ou been to the Bigelow brook farms site, or blog? Try doing a google search for Bigelow Brook Farms and click on that link to You tube , while not
about gold fish, if you haven't been there even just this week you have missed something ! Best ! PYRO Big AL !

I'm curious about goldfish myself. I have a couple of small ponds in my front yard, and a neighbor put a few goldfish in a year or two ago
and now I have hundreds of them.

So far they seem pretty happy being fed a few times a day.
I also make sure they have places to hide, they seem to like hiding under floating plants in the heat of the day.

While not having a lot of wisdom to share myself, I can suggest another forum I frequented years ago, http://www.kokosgoldfish.com/ , which has vast amounts of information on goldfish. I seem to recall there were some people there using goldfish in aquaponics systems, although most of the people there treat their goldfish like their own children. If you want to know how to keep your goldfish at their healthiest and happiest, I don't know of a better place to start.

I admire your concern - most people in aquaponics are simply content with fish that are alive and healthy.

However you're asking a fairly existential question. Do we really know if the word "happy" means anything for non-human creatures? Do fish have the capacity to be physically thriving but unhappy?

I've noticed that my tilapia get more excited when their food is fresher.

In terms of unhealthy fish, if you start to see a coating over their eyes, or if they start to swim sideways, those are signs of un-health. If you find an occasional dead fish that's probably a sign that the rest of them are stressed.

Most fish deaths I've caused and heard about from others have been related to not enough oxygen.