Hi again Katie,
Most people wouldn't think that a 29US/24UK would be enough for all those fish either. I am not sure though as I have mine in a tank only a bit bigger (41US/35UK) and I think mine are fine.
What is the tempature of your tank? The CAE is a tropical fish and will need a tempature of 75F/25C but a bit higher is better. Unless your tank has a heater, is in a hot room or maybe beside a radiator then I don't see your tank getting to this tempature. Many people do heat their goldfish tanks and I think it's quite good forthem as long as it's not too high. However, I don't think the CAE is suitable for the tank in any case.
In the first link I gave you it says:
"Because they tend to grow rather large, they do much better in a large tank of at least 75-gallons."
and
"They are known to harass and terrorize tank mates. They can also attach themselves to the sides of other fish, which can seriously injure the other fish."
Did you read this? I seriously advise you to take the CAE back or rehome it, explaining why and making sure it is suitable for the new owner.
I would never keep them and IMHO you are not equiped to by way of space or requirements to look after it. Also, it may harms your goldfish later on and they don't have much room to get away.
Maybe you could get another type of these, if you were willing to heat your tank a bit, when you get a bigger tank. I am getting Siamese Flying Foxes (also known as siamese algae eaters) on Friday and these are different to the Chinese ones. They are not aggressive and will be very happy to eat algae as long as it's there.
This link gives information on both the Siamaese Flying Fox and the Chinese Algae Eater -
http://www.fishpondinfo.com/sae.htmFor just a pic of the SFF -
http://www.aquazoo.co.uk/Page.cfm/Type=Fish/ID=271 but this has little information.
You should have have a look, it's pretty useful as it's got them both together.
Let me know what you think of this, Dana.