sirdarksol

I have a goldfish and a koi that will be getting a new (larger) tank soon, as the koi is likely to outgrow the current tank pretty quickly.
It's pretty likely that I won't be putting a heater in the tank. My house remains a relatively constant temperature, due to the AC/heater being kept at a constant 68 degrees F.
I know that koi and goldfish don't need the typical tropical temperatures, so they'll be fine in this tank, as long as I make the change gradual for them.
My question is this:
I would like to have a tankmate or two for them, particularly at least one algae eater. Are there any good, non-goldfish that deal well with colder water?
Another variable to throw into the mix is that my koi is kind of aggressive. This means that whatever tankmates he has will either have to be able to deal with aggressive fish or will be able to outrun/hide from him.

genie

You really can't mix any tropical with Koi or Goldfish-- their needs are just too different. Also, your Koi and Goldfish will probably get big enough to eat a lot of other fish-- if it will fit in their mouth it might be dinner. I am not sure, but I think both koi and goldfish will eventually get really big and be better suited in a pond. I hope this helps-- sorry to be a spoil sport. Maybe someone else will be able to help you more.

sirdarksol

I know the koi is going to get big, but it takes them quite a while. I should have at least a few years before my koi outgrows the tank I'm building for it. And, if it was any koi other than the one I own, I wouldn't be worrying about aggression. Koi are smart enough to recognize fish as "not food."
And I just noticed there is a goldfish section to the boards. Sorry, should have put this there.
Thanks for the info.

Neville

hi, it's neville, i think the best tankmate for a goldfish is another goldfish ...............the koi that u r talking about...is it a buttrfly koi or a koi carp, because carps also grow big.....butterflies r very aggressive, i don't know if it is safe to keep a goldfish with them or not.............what is your tank size?

sirdarksol

The koi is a part butterfly. He is somewhat aggressive, but only toward really small things (snails, the otos) and me, if I'm intruding in the tank.

Current tank is pretty small, next tank is going to be around 70 gallons, but is going to have a much wider footprint, which is what is more important for a koi than gallons (I've been studying koi for much longer than I've been interested in actually raising fish)

Sounds like there aren't any coldwater fish other than goldfish. Makes me sad But as there's little I can do about it, I'll just have to deal with it.

Thanks again for the input.

JMatt1983

fortunately, there are many different kinds of goldfish to choose from, also, you have to think of the life expectancy of goldfish and koi, i've heard of people keeping for up to 15-20 years

sirdarksol

Yep. Actually, there is one koi that, according to tests done on her after her death, was 250+ years old. She was just a family koi raised in a little pond out in the garden. She was passed down from family member to family member, survived two world wars (I think she actually survived a bombing of the neighborhood).
They are amazing creatures. If you can keep them from succumbing to illness, they can live a very long time.

Neville

wow, 250 yrs old fish!!!! andi thought only turtles live for 200 yrs!!!!

Shastam

The only thing you can really put with goldfish is other coldwater fish. Some species of loaches are ok with goldfish as long as you have a tank large enough for everyone to live in comfortably.

gremlin

You might want to try one my sister told me about. a garra pingi pingi. Yes, it is a funny name. She tried one in her pond but it was just too warm (phoenix - desert - HOT). I looked it up and they do require cooler temps (55 - 70 I think it said).