Just wondering if I can mix a koi, goldfish and a betta?
The temp in the tank is 72. degrees
will they fight?

bettas and goldfish dont mix, betta like warmer temps and they nip the fins of goldfish and the koi will eventually get larger then 2ft and the betta will make a delicious snack for it, and the koi will out compete the goldfish for food and the betta will just starve.on a side note what sized tank are these fish living in

Nup, koi grow too fast, eat too much, poop too much, bully other fish and like cold water... your betta will hate a koi and koi conditions.

Why arent you listening? Are you going to go to every forum and ask the same question until you get the answer you want? It doesnt matter how you rephrase it you shouldnt do it.
Bettas are tropical and should be in their own tank and where did the koi come from? Last time it was just the goldfish.

Your koi will need 250 gallons of water, and the goldie 25 gallons, i dont think your tank will be big enough.

I've just read ur thread in the other forum, Ihave2goldfish, and I think u need to respect the more experienced fishkeepers here and there. They know what they're doing and have given u lots of good advice, only for u to completely go against those advice, unfortunately, at the expense of your fish.

You're lucky this forum is much more friendly than the other one. If not for the rules here, I'd use the same kinda language some of the members in the other forum did.

Hmm.. well, Ihave2goldfish, I don't understand the point of posting a question and not listening to the advice people are giving you just because you don't like the answer to it. Doesn't make much sense to me, sorry

I agree with everyone, especially on the Koi.... Bad scene, they are pond fish and not a tank fish. A Betta is not going to be anything more then a light snack to goldies, most likely the koi.

I can't think of a single board around online that will tell you different either.

If you ask me, I'd never mix a betta with another type of fish because Bettas (especially males) tend to nibble on other fish's fins. They also get in lots of fights. I'd also advise any new betta owner to:

NEVER PUT 2 MALE BETTAS IN THE SAME TANK!!! I've seen it happen and the results are not pretty. I think it's fish crulty

im with everyone else
just not a good mix, although the good news is you could keep one if you got a very small tank (2 gals or so).

yeah, you can keep the betta in a smallish container like a fish bowl in a warm room. the koi i would advise you either get a very large pond for him or let him go to someone who has the room. im not just saying this to spite you but they do grow extremely large and need AT LEAST 250 gals just to survive with the amount of muck they make. the goldie can stay on its own but please, i beg you, do not put the betta with it. be a resposible fish owner and let them have their own space in their own prefered waters. eventually the betta will become food for the goldie which will become food for the koi which will grow too big for the tank and eventually die. if you intend to keep at least one fish alive id advise you follow some of the instructions me and other members have spent the time writing for you