The biggest problem you are having
D
Dan30
is most likely because the chocolate was already established in the tank, and sees the tank is their territory. So another large, similar-looking fish entering the territory is a threat, explaining why he was attacking him. Re-arranging the tank (or even better, bucketing the fish and completely re-doing décor, not just moving the same pieces around) are probably your best bet for getting the chocolate to forget he's in his own territory and possibly easy his aggression.
Other than that, a divider is an option, though this isn't ideal since it will cut each fish's swimming space in half.
I also find that 2 cichlids in a tank rarely works out unless they are more placid (oscar and chocolate IMO would usually fall into this category) because whoever is dominant bullies the other one, and the subdominant one has nobody to share in the stress, and suffers. When there are multiple subdom fish, the aggression is spread around and they aren't singled out.
So re-doing decor and adding one more similarly sized and tempered fish, might be a good strategy. I would suggest a severum for the other species if you were to go this route.
No guarantees any of this works of course, it is up to your chocolate in the end.
Side note- I would definitely not keep cory cats with an Oscar, they will try to eat anything that fits in their mouth, and the corys have spines on their fins that cause them to get lodged into the predators' throats. I had a cichlid eat one pretty recently and he had to have surgery with a pair of pliers to get it out. Very stressful!
Other than that, a divider is an option, though this isn't ideal since it will cut each fish's swimming space in half.
I also find that 2 cichlids in a tank rarely works out unless they are more placid (oscar and chocolate IMO would usually fall into this category) because whoever is dominant bullies the other one, and the subdominant one has nobody to share in the stress, and suffers. When there are multiple subdom fish, the aggression is spread around and they aren't singled out.
So re-doing decor and adding one more similarly sized and tempered fish, might be a good strategy. I would suggest a severum for the other species if you were to go this route.
No guarantees any of this works of course, it is up to your chocolate in the end.
Side note- I would definitely not keep cory cats with an Oscar, they will try to eat anything that fits in their mouth, and the corys have spines on their fins that cause them to get lodged into the predators' throats. I had a cichlid eat one pretty recently and he had to have surgery with a pair of pliers to get it out. Very stressful!
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