Tilapia in with goldfish and koi?

[Jim S.]

I bought some tester goldfish to put in my 250 gal tank which is heated to between 70 and 80F and then bought a few koi after it seemed the goldfish were doing fine. All seem to be doing well after a few weeks. I'm now looking to add tilapia.

Does anyone know if the tilapia would get along ok with the other fish?

[Alexandre Letellier]

Hi Jim, I haven't done it myself but I've asked the same question a bit earlier in this forum and it seems that yes, tilapia and koi can live in the same tank. I was told that catfishes can also be added...  3 species in the same tank is kinda nice  :)

[Chip Pilkington]

Hi Jim,

I have both Koi and Tilapia in my large tank and they have been coexisting with no issues for about 8 months. I use Koi from my small pond to cycle my tanks (I'm one of the few who does not practice fishless cycling these days).

I participate in a few of the Aussie forums - there are several others in Asia and Canada who successfully mix the two as well (Tilapia are illegal in Australia).

My plan was always to move the Koi out...but I ran out of room as the Tilapia multiplied. Now I'm kind of attached to them. They are very friendly fish, especially when you've got food for them. Anyway, absolutely no worries mixing the two.

[Jim S.]

Well thats good news. I appreciate the info.

I had been considering adding catfish too.

[Chip Pilkington]

I have had the Asian eel-tail catfish in with them as well in my pond. Keep in mind most catfish are serious predators and will pick off anything they can fit in their mouths, like young Tilapia, should they begin breeding. I eventually moved mine out for that reason.

[FormulaX]

Chip is right, the catfish can pick off the small fry offspring of other fish, and since Tilapia are cichlids, they can have an aggressive temperment, I havent owned them yet, but the cichlids that I have owned, can be very agressive.  Sometimes it depends on how you introduce them into the environment, but I could easily see a cichlid eating a goldfish that is much smaller.

[Chip Pilkington]

It's interesting, because I've have various cichlids over the years - oscars, convicts, peacock bass, etc. I think overall, the Tilalpia are much easier on their tankmates. When they start the breeding games, the males can get a little rough but I've never had a fish injured (knock on wood). Living in Thailand, of course mosquitos are an issue. I keep "guppies" in my pond, along with the Koi and Tilapia. Believe it or not, they seem to do ok together. I'm sure the guppy fry don't last long, but the adults do great and really help as they love to eat mosquito larvae. I would be cautious but I'm thinking all but very small goldfish would be ok. Tilapia really aren't the big predators that some of their cousins are. Their natural diet leans much heavier towards vegetation. Of course most fish are opportunistic and Tilapia will eat live food, so just be careful if you're attached to the goldies.  

[Chip Pilkington]

I had a think about my previous comments - Goldfish living with the Tilapia. Here in Asia, we have dozens of Golfish varieties, many big, chubby varieties that would choke a great white. Depending on the size and variety, it may or may not be a good mix.

My fish of preference for cycling in the States was Comets. Here I use small Koi. They will grow with their tank mates and generally do fine. They end up becoming pets and stay in the system indefinitely.

[veronica moore]

I have one talapia  tank and one koi smaller pond  that also has some kind of wild smaller fish like killies or mimmos that are multiplying too much if I put some in the talapia tank would they be food for the bigger fish because the koi don't eat them and they are taking over the koi pond?  Thanks for all your input

[Garrett Van Neste]

Thank you for the post :) I've done a similar thing (Started with goldfish, then added a few koi).  I've been interested in adding a couple catfish to my FT too.  It sounds like some people have had success in doing so, so I think I'll have to try it!  Since catfish can be fairly predatory, I would imagine it may be a good idea to buy them smaller than my goldfish/koi if I can, any thoughts?

[D Mauro]

I added 2 small tilapia to my 250 which currently has 12 large goldfish.  This was a test to see if they could coexist in a large tank where crowding wasnt an issue.  For a week or so everything was calm.  During the second week I started noticing some fin damage on the goldfish.  This came to an end when I woke up to find 2 of the goldfish badly hurt on the surface.  Both goldfish subsequently died and the  2 tilapia were moved back to the general population.