I have a 125 gallon tank I setup.

Currently I have 3 2 inch tiger oscars and a 2 inch jack dempsey in the tank.

I wish I had found this forum sooner or I would have gone with just one oscar.

Am I going to have problems with 3 oscars?

Will my jack dempsey be an issue?

I think I'd like to have a juripari in this tank and maybe clown loaches or a pleco?

I'm kind of new to keeping large fish like this. I'm not sure how to judge what would be enough fish.

For filtration the tank has two eheim pro II canisters.

firstly, welcome to the site

now to the tank. how many gallons your tank is, is important when dealing with larger cichlids however the footprint of the tank also plays a part in how many fish you can keep. if you could post the dimensions of your tank it could make it easier to provide you with a more accurate course of action you could take.

as far as three oscars go i personally wouldnt risk it. the odds are good that there would be some issue that would eventually creep up such as a breeding pair or territorial disputes.

for you jack dempsey only time will tell. some jacks are fine as tankmates while others can be more aggressive.

your filtration should be adequate for your tank size.

and finally for adding more fish. personally i think your overrstocked with the three oscars and the jack. now if you were to rehome one oscar you should be able to add one mid size tankmate but again it depends on the footprint of your tank

at 125 gal.... 2 oscar and 2 jd will be fine.
as necro said, only time will tell if the jd
will become aggressive with the oscar.

3 oscars is always considered a bad number. the
logic there is that once pairing is established,
the outcast will be bullied and driven away. if they
happens to be all male, territorial supremacy is
another issue. if happens to be all female, they will
get along all the way with occasional sulking to
each other.

ive been overstocked more then that, but with adiquite filtration and some luck. your water levels and aggression will be fine. like everyone else said only time can tell if your jack will become agressive towords the oscars. ive had mixed results, in one case i had 2 jacks that ended up pairing and breeding. they didnt bother the oscars as long as they didnt go near the fry. so they knew to keep away

in 2 other cases, i had o's and a jack in 2 different tankes. the larger ones were just about fully grown when the jack killed them pretty much over night. in the other, they were about 5'' when the jack did the same thing a couple months later.

be sure to have a lot of hiding spots, not so much for the oscars, because oscars really dont hide much, but for the jack. maybe he'll find a cave he really likes and just hang out there and defend his spot. thats probally your best bet

if I were you I would wait and see what happens. ok, three oscars might become a problem but you can always sell one when the problems starts. who knows, maybe you end up with a breeding pair.

I'm contemplating giving 1 or 2 of the oscars to my local fish store along with the JD and just going with more of a variety of fish. I know I want at least an Oscar though

I've already noticed the JD being aggressive at times with the oscars. I've seen him nip at them and they seem to be afraid of him. Since these are 2 inch fish I'm thinking thats not a good sign.

smikeb wrote:


u should only keep 1 or 6 or more no less than 6 if u want more than 1 as oscers like to fight and less than 6 would be unfair as the strongest would cause suffering to the others

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from my experience ive notice that multiple oscars are fine together provided you have a big enough tank for them. however you should only keep even mumbers until you get to six. after that it only comes down to tank size.

dogchain65 wrote:


hhmmm.....so what you are saying is that oscars fight...or what?
why not wait until there's a problem....then you solve it.

happy fish keeping should start in a right tone. hobbyist
should be happy and the pet as well. i can not imagine myself
separating from my oscars after several months of caring just
because of some territorial issue or bullying.

just my two cents opinion

I agree with the previous poster. I'd rather take care of any potential issues now instead of waiting till the fish are larger and more difficult to deal with. I think I'm gonna just donate 2 of the oscars and the JD to the local fish store and keep one oscar. From that point I am looking into silver dollars, tin foil barbs, some type of catfish and a big pleco