I too am a big fan of keeping it alone in it's own 10 gal. This will ensure that even if you don't see the fish eat if the food is gone, you'll know he ate it. Plus with one that small you'll ensure he's not over competed for food. Diesel mentioned dried krill. This stuff is amazing. I have brought many small cats out of a hunger strike with this stuff. You know what you are doing and you have plenty of room for him in the future. What's the dimensions on your 1200?