I decided to take a look here again and sturgeon are the only fish I know much about so I guess I'll share my thoughts. I see Chub_by replied already which doesn't surprise me
. As far as I know he knows his stuff and I agree with what he already said.
You seem to be new to keeping sturgeon? I'll answer your questions and give you some general advice.
So any ideas for a sturgeon for me with these requirements?
1) Preferably from North America, only non North American species I'd like for now would be a Sterlet.
2) stays under 5' or so with 4' or less being preferred. If it got bigger than that I'd be fine with it as long as it took a long time to get that big since once I have my own place in about 6 years I'll be putting in a much larger pond (tank and pond space are going to be major factors when I buy a house
)
3) Not very difficult to keep and can hold its own against other fish like larger catfish and sunfish.
4) Not incredibly hard to find or very expensive (so should be under $100
5) Not a picky eater (Im willing to feed frozen every night but not live more than every week or so)
Any Sturgeon in your guys experience that would fit these requirements or should I just wait 6 years until I put in a massive pond and get a White sturgeon?
1: From (or available in) North America, this gives you a couple of options:
White sturgeon, Sterlet, Shortnose sturgeon, Atlantic sturgeon, Shovelnose sturgeon, Pallid sturgeon, Green sturgeon, Paddlefish.
I'm listing almost every species in North America (except for the Lake sturgeon) because I'm pretty sure these are all being bred. Most of the breeding is done for, or by the government though since they are needed for restocking. I know for a fact that there have been Shovelnose and Pallid sturgeon for sale in Europe (very limited). But I hear the biggest problem is getting them out of the states, since you live in the states (I assume) you may be able to get one of these.
Shovelnose: Stays small, similar max size to a Sterlet. They are not commonly for sale. If you can get one this is a suitable species.
Pallid sturgeon: Basically a light coloured Shovelnose on steroids, gets to be about twice as long.
White sturgeon: As far as I know, commonly for sale in the US, also commonly mislabeled as 'Sterlet' to fool people into buying one. As you know these grow to enormous size, they are the second or third largest species of sturgeon in the world.
Green sturgeon: A species that can grow very large as well, a nice species similar to the white sturgeon. As far as I know they are not commercially available (yet).
Sterlet: As you know, a small species of sturgeon. They should be pretty easily available to you.
Shortnose sturgeon: A nice species, looks like a bulky atlantic sturgeon with a shorter nose. They can grow up to 1,4m, a bit smaller than a diamond sturgeon but bigger than a Sterlet. They are being bred in Canada but are illegal in Europe, I am not sure if you can get one through a shop but it could be possible.
Atlantic sturgeon: One of the nicest looking species. They are rare in Europe but they are commercially available here. They are bred in Canada and the USA but I don't know if shops actually sell them. The problem with this species is the max size (4,3m). Not a small species.
Paddlefish: Probably the oddest looking sturgeon one can buy, they are becoming more common in Europe. Since they are native to the US and being bred there it may be possible to buy them. They do require some extra attention since they are built for filter feeding, some individuals adapt better to different foods than others.
They can potentially become quite large (2,2m) but I've never seen one close to that.
2: Regarding your size restrictions, the following species could work: Sterlet, Shortnose, Shovelnose and the paddlefish.
3: Your average sturgeon is a very hardy fish. If you compare them to Koi they are more resilient to parasites, have tougher skin, and can survive accidentally jumping out of the pond longer. Your number one concern for sturgeon should be to keep the water well aerated. Use a good oxygen pump with a huge (or a couple) airdisk(s).
As always, set up a proper filter, toxic ammonia / nitrite levels will kill any fish.
The paddlefish is the one I would be more careful with though.
4: Under $100 should be easy. I don't know about pricing in the US, but any of the species I mentioned should be available for far less, depending on the size. $100 should get you a pretty big sturgeon, no matter the species.
5: Every sturgeon can thrive on good sturgeon food. The only sturgeon that could need different food is the Paddlefish, due to the fact that it's built for filter feeding, other than that you shouldn't even bother with live food like worms, or frozen shrimp etc. These are only needed when you have a sturgeon that is not trained to eat pellets, or has health / eating issues.
If you feed quality sturgeon pellets, they absolutely do not need anything else. Anything else you feed is just 'extra' or for your own amusement. It will not benefit the sturgeon.
About getting a small sturgeon and raising it in an aquarium, I agree with Chub_by that sturgeon are not aquarium fish in the sense that getting one to keep in an aquarium (unless you're rich and have a 10x10m aquarium to put them in or something) is a bad idea. However, you could probably raise one to a more suitable size for the outdoor pond. I wouldn't keep a sturgeon bigger than 40cm in an aquarium though, at that size they should be able to do well in a pond.
keep in mind that when you keep one in an aquarium or pond with other fish, you need to monitor it feeding since sturgeon are slow eaters. Other fish may steal their food.
Also, really tiny sturgeon (below 15-20cm) are notoriously difficult to keep. If you get them at this size prepare to lose it / them. They are still weak and have no energy reserves to speak of. They also need to feed constantly which few people know or can provide. I believe sturgeon smaller than about 30-20cm need food every 4 hours, this means you need an autofeeder or they could die. Bigger sturgeon can easily cope with 1 feed a day or even less, once or twice a day is ideal though.
About growth rates, Sterlets and other small species should grow slowly. White sturgeon can grow quickly to 1m, I'd say they could get there in two or three years. In good conditions they will grow about 10cm each year between the 1m-2m mark, from 2 meters onward they will only grow a couple of cm to 5cm a year.
Lastly, keeping your plans in mind, I suggest you plan a bigger pond. Your max pond size sounds ok for a Sterlet or Shovelnose but that's about it, maybe a Paddlefish as well.
If you have any further questions feel free to ask