The Red Terror would kill the FH in a 125 so scratch that idea. I believe someone stated a midas/Red devil in a 125. I'd think the midas/red devil would kill the FH also, but not sure.
why would the fh kill the oscar isnt the o goin to grow twice as fast and always be bigger until fully grown, rd maybe and then maybe a trimac or red terror so waht you guys r sayin is if i like the fh get rid of all the rest and start from scratch i dont waht a one fish tank , what goes well with fh in your experences in a 125
Flowerhorns and oscars are BOTH very quick growing fish. They will both soon outgrow that tank. If you like the flowerhorns, you are going to need a very large tank to keep them with any tankmates. I have one in a 220g, and he still chases all his tankmates. Also, mine is STILL a juvie. The only way to keep aggressive fish together is to give them lots of space, i.e. a very large tank (200+ gallons). I know you said that yours is a fairly peaceful fish, as it grows, it's temperament will get worse. It will become very aggressive as it reaches sexual maturity. That's just how it works. Start coming up with a plan now, and you may be able to make it work.
the flowerhorn is not going to be compatible with anything in that tank, so you might as well get that thought out of your head, (even the convicts will probably put up a better fight then the oscars lol). If i were you id replace the oscars with five star generals or if you cant find them regular jewel cichlids. Then replace the fh with a grammode.
So the stock list would be
1 five star general (jewel)
3 cons
1 grammode possibly 2
id replace that cat with syno
and if you want to overstock get a texas. Idk if you like hybrids but id look for a texas/jag as a show specimen for the tank.
Yeah 125 would work without the FH or with something in place of the FH. Like swap the FH for a JD and maybe you've got something. Also unless it gets really huge you have a good chance at losing your shark, I have seen occasional big ones and if it gets big it might hang in there. You may or may not lose the danios, I've had oscars that left GD's alone but had one recently who insisted on eating them.
Oscars are one of the if not the weakest large American Cichlids around and many FH are crazy aggressive.
I don't know about a Festar taking a FH-for one Festae grow really slow and the FH will outgrow the Festae-secondly-I have seen Festae kept with Oscars at Cichlid Scene yes some Festae can be aggressive but not as aggressive as a FH.