What is a loach I never owned one? And do they get along with fantail goldfish in a 20 gallon tank? What do they eat?

Get a weather loach or dojo, as it's commonly called. They are great companions for goldfish. They will burrow around the gravel looking for uneaten flake,bloodworms, etc. You could give them some sinking tablets as well, but basically they eat what the goldfish eat.

Below is a picture of my 2 'loaches'

They are weather loaches or commonly called a DOJO. They get along with all my goldies. I have orandas, a common, a moor. They all love each other. And the Weather loach is loads of fun to watch. Just make sure if you get one that your tank doesn't have any openings larger than an inch as they are notorius for jumping out.

They swim very very very fast. When I purchased mine, the store owner couldn't catch them. The Dojo's literally jumped out of one tank and into the one next to it. I laughed so hard my fiance thought I was weird. ( What else is new.. haha)

Mine just eats the goldfish food that floats to the bottom, and digs around in the gravel for leftovers. It also eats pellet food and veggies.

I have a pair of Dojo loaches myself. They are the most hilarious fish!! The other day I looked in my betta tank,and could only find one.I started to panic because I thought maybe he finally jumped ship,and as I started to take a step back to look on the floor a movement in the tank caught my eye.-It was the other loach buried in the sand up to his eyes and whiskers!!! Funny as heck! You can't appreciate a loach until you see them burying theirselves in sand! I plan on getting even more of them!