Wanting to try other fish maybe goldfish?

[a123andpoof]

Okay so while I love my betta's I really want a community tank or you know something not divided. I have an empty or almost empty 10g and a space I can add a larger tank, but nothing to huge.
What size would be a min for goldfish?
What are some good fish for a 10g with a betta? I am leaning towards getting a king or plakat for my empty 10g and then getting a few other types of fish to throw in there. Any suggestions? I havent owned any fish other than betta's but am always admiring them goldfish, and bala sharks in particular.
What size for bala sharks now that I am thinking about it?

[Olympia]

Bala sharks are a schooling fish that hit 14" and require at minimum a 6 foot long tank to live in, even that is small though for an extremely active fish.
Goldfish, you could probably do a pair of pearscales, celestial eye, bubble eye, or ranchu, in a 30 gallon with good filtration, but some of them do come with their own health concerns like bloating.
Maybe some cories for the 10 gallon?

[LittleBettaFish]

Bala sharks and goldfish both grow too big for a 10g aquarium. For fancy goldfish it is like a 30 gallons minimum and stock standard goldfish do better in aquariums over 100 gallons or in ponds.

Bala sharks grow to around a foot long and I believe once they reach a certain size they start running into the glass and hitting the lid of their tank. They are also a schooling fish so you would need a tank big enough to hold several 13 inch fish.

Depending on how hard or soft your water is, and whether your betta is overly aggressive, smaller rasbora species might be the way to go. I have some lovely microrasbora kubotai, but CPDs, boraras maculata, boraras brigittae or even some emerald eye rasbora would be suitable.

Of course the price on these fish is more than on something like a guppy, and they can be sensitive to poor water conditions, but I think they are very well-suited as tankmates to a relatively peaceful male betta.

I see you Olympia haha sneaking a reply in while I was typing

[Olympia]

Happens a lot, doesn't it? Didn't have any ideas for the 10 gallon, quite uncreative. I love CPD's.

[a123andpoof]

Wonder if I could fit a 30g in the space I am looking at.

I am looking at the shubunkin goldfish, and telescope eye ones or really just any that come in a calico coloring. But more so the shubunkin how would they do in a 30-35g? And would that be just 1 fish or 2? And could anything else such as like a bottom feeder or something also go in there?

[a123andpoof]

I knew goldfish could not go in a 10g wouldnt even dream of it! I believe my water is fairly soft but I do have hight Nirtites I think thats the right one...should double check.

[Olympia]

Shubunkin is a single tailed goldfish that needs a 100 gallon.
Telescope eye goldfish are your better option as they will stay small for a fancy. You could do 2 fish in a 30-35 gallon.
Some fancies like black moor or oranda you should avoid as they can still easily get to 10-12"

[LittleBettaFish]

Do you mean high nitrates or high nitrites, which are toxic and can potentially kill your fish?

CPDs are nice. Mine aren't as shy as people say. They will swim over to the glass to come and see what I am doing, but I have about 30 odd schooling fish in that tank so they have a bit more confidence.

I personally like the look of Microrasbora erythromicron, but they are quite rare here. Another suggestion is lamp-eye killifish as aside from their eyes they are not very brightly coloured.

[thekoimaiden]

Olympia and LBF have hit on some of the main points, but I will reiterate a bit. I consider 30 gal as the minimum for goldfish. Really any smaller and you're going to run into physical issues as well as nitrate control. Of the goldfish that could go in that tank, you're going to want to look at the more physically modified fish like celestial, ranchu, and bubble eyes. Those tend to stay smaller. They also have more trouble swimming so they don't need as much room.

As Olympia and LBF mentioned, the single-tail goldfish won't do well in anything under 100 gallons. Really they won't do great in anything shy of a large pond. That being said, there are calico varieties of other goldfish like ranchu and ryukin.

As far as another fish in the 30 gal with two goldfish, I think that's pushing the bioload too much. You are already going to need to have a large filter to take care of the goldfish waste. A lot of bottom feeders are high-waste fish. Plus, pleco have been known to suck on goldfish's slime coats.

If you have soft water, you might have trouble with goldfish. They are a hard water fish. In soft water, they can experience slime coat loss. Without a high KH, the pH of the water can experience rapid drops as the week goes by.

By telescope goldfish, do you mean these? Those like oranda and fantails tend to get pretty large.

[a123andpoof]

Its the nitrates it isnt super high it is in the safe range but it doesnt go down to like zero either. Just wondering if that would still work. I think I am going to pass on the goldfish for now. Maybe when I move and can get more space. But would still like ideas for maybe a 20g community tank. I dont know a ton about other fish so anything that can live with a betta. If I do that I would probably transfer the king I have now. What could I put in there? I know I have a few more options with that.