I wouldn't put any koi, no matter what size in a 150 gallon pond. They will eventually grow too big for the pond. I'd stick with goldfish.

Look for Shubunkins. They are goldfish and are 3 colored. Some have metalic looking scales. I love them and have 6 calico fishes in 2 ponds.

NO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Sorry for the vehement response but that garden center guy who told you that is perpetuating a myth that is responsible for a lot of fish deaths and a lot of koi and goldfish having miserable short lives when with proper care, they can live 15-20 yrs - OR MORE. He reallly ought to know better.

Koi's natural size is 2-3 feet long. You keep them in a cramped space where they cant grow properly - the internal organs will continue grow, the body really can't - the fish becomes physically debilitated, stressed and susceptible to disease. They dont "stay small," its more like the fish die young. That's how they "stay small."

Aside from the health and well being of the fish the question comes to mind- WHY? Why even attempt this when there are many comet goldfish with long fins/tails, calico shubunkins with amazing colors..... even a lot of new types of brightly colored goldfish that have been bred for ponds - Ive seen some that are solid metallic blue and some that are a bright clear yellow (might have to look for speciality shops).

About 3-5 goldfish is all you want in 150 gals. No koi please! You want to allow enough space to be able to see your fish swimming freely and moving around in a school - very restful to watch. Its so sad when I see large koi having no room to move and just lying there like sardines in a can. For a fish, koi are reasonably intelligent, and need room to dive and excercise - at least 4 feet deep is recommended. More if you got it!

I do hope that is helpful info .... and I appreciate you coming to check it out prior to fish purchase. For many of us our fish become beloved pets, not as brilliant and clever as the cat perhaps but a beloved pet nevertheless. They know who theyre owners are and who feeds them and follow people they know around the pond like puppy dogs. If you really have your heart set on koi.... pls, pls research and plan a bigger, expanded koi pond!

Your pond is way too small for koi. They get big and need proper filteration.

We have Koi for 17, 18, years ... our oldest koi will be 19 in September.

They need lots of depth as well as surface swimming room....

take current residents advise.

Awww that is so sweet cliff and joann that you know what month his (her?) birthday is! Errr do I mean "spawn-day"? Or do you celebrate the date of taking residence in your pond.

My oldest fish, Big Red, is at least 17 or maybe even 18 - got him in spring 2000 from a pond store. Pretty soon he'll be asking for the keys to the car LOL. He's an example btw of a good fish for a small pond - a solid red comet with unusually long flowing fins - even for a comet they're long. Has more of a koi build to him too so I wonder if he might be a mix.