What kind of 125 is it? 125 tall, 125 wide? A 125 wide (24") should be ok for quite some time with a Florida but now you could possibly have a problem with the JD since cichlids and gar aren't the best tank mates. Depends more on the JD's temperament. For feeders none are really the best but if you have to fatheads are better than goldfish, actually dirt is probably better than goldfish. Try freeze dried krill and market shrimp, you might have to work with him to get him off live food but its healthier and cheaper in the long run to get them on prepared food.