Dude, don't give him feeder-fish, he'll be infected with God-knows-what in no time. Those things are filthy and riddled with bacteria, parasites, fungus,....who knows. jags are highly piscivorous, but there are much safer ways of including fish in their diet, like slicing bite-sized pieces from frozen-thawed fish fillets. Fillets of fish intended for human consumption have many times more nutrients and protein than goldfish or rosys. Feederfish are very fatty and oily.
To be safe, I would quarantine at least a month if you have been giving him feederfish, and might be safe just to treat him with an All-in-1 medication for parasites/bacteria/fungal before putting him in your main tank. medicating a 250 gallon tank will get very expensive very quickly. Stick with shrimp, krill, crickets, earth/wax/meal/butterworms, clams/oysters/mussels......seafood that has been frozen and likely killed any harmful pathogens. if you want to feed live, crickets and worms are safest.
No worries, I have already asked a Mod to move it to SA/CA Cichlid sub-forum.
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