This is not a heated tank but my tank temperature usually stays between 70 to 78 degrees farenheit(21-27 celcius).I change the waterevery 2-3 days
Answers:
You can get a dwarf oto which are small(1.5 to 2inches) and can be in your goldfish proper temperature of 65degrees farhrenheit to up to tropical tank of 74-80degrees.
And also you need to get a larger tank for your goldfish(all species and all sizes need at least 25-30gallons of water each) and needs colder water as well.
corydoras are the best bottomfeeders in my opinion
chinese algea eaters
otocinclus is a good algae eater because it stays small
There are several algae eaters that would be fine with a goldfish, but not in a 14 gallon. You should stick to old credit cards for scraping the glass. If you want algae eaters, you need to find a new home for the goldfish. Otocinclus would be great minus the GF.
A good Algae eater would be a Dwarf Otocinclus catfish they will stick to your glass of the tank the bottom your deco. and there fun to watch. I will put a couple links below that you can read up on the oto. These catfish don't get real big Chinese algae eaters I have a few of these oto. and I only have had one die. And i believe they were a great investment in my tank. Good luck.
If you don't want plecos or snails it is pretty much narrowed down in selection. Most live bearers are algae grazers and would be the best choice in relation to getting along with your goldfish based on his/her size. I wouldn't recommend any type of cichlid, which are algae grazers also, due to their fired up aggressive attitude. A final recommendation is a river loach. They are bottom dwelling and will nibble on algae but have two thorn like spines which serves as a defense. Also, hence the name river loach...they need a fast flowing tank. Clown loaches are a good choice but usually require a larger tank. I myself would keep it simple and go with a few live bearers but not too many based on the 14 gallons. Hope it works out for ya and good luck!
