My goldfish tank, ghost shrimp and guppies

Question
Okay, I have a 10 gallon aquarium right now. I have 2 goldfish and one koi. I also bought some ghost shrimp so that I could have something else in my tank. I also have 2 ornaments for the shrimp to hide in. Now the larger of my goldfish is about 3"-4" and the Koi is about the same. And those 2 try to eat the ghost shrimp, which is okay with me. Now when I go to wal-mart to get ghost shrimp sometimes I inadvertantly get a guppy. I don't mind this either. My question is what can I buy so the guppy has a better place to hide because my goldfish keep attacking the guppy. The first guppy was eaten, this one will probably be eaten too. But incase this happens again, I'd like to give the guppy more of a fighting chance to survive.

Answer
Hi John:  Lets start with the Koi... beautiful fish that are extremely aggressive... Goldfish and Koi are both coldwater fish that should really not be kept together except by the most experienced of pond masters... as the koi will eat your goldfish one bite at a time.  A ten gallon tank is too small for three medium sized fish and a guppie... Goldfish typically need ten gallons per fish under 4 inches.  What is going to happen is that your tank is going to get more and more dirty until the fish get sick and die.  What I would do if I were you is this... invest in a 20 or 30 gallon tank and a filter... this should cost you under $75 in fact you might be able to find a 20 gallon kit for much less.  The ten gallon tank would then become home to the guppy and the ghost shrimp.  If you are unable to get a second tank... then I would invest in a large and bush plastic plant for the guppy to hide in... hope this helps... dave