Bichir question

I picked up a few bichirs which are still fairly small. The youngest being a 2.5-3" Delhezi which still has his external lungs. He spends majority of the day in the plants near the surface. Should I put him in my breeding box on the side of the tank until he loses his external lungs? It holds .5 gallons and water flows in and out from my main tank, it measures 10.7" x 5.8" x 5.7" so he can still move around quite well, here is a link to it. The main tank is 125g which is probably a little big for the little guy, might be difficult for him to find food.

The others are Endlicheri's and they are in the 4-4.5" range and seem to be finding food without issue.

He tends to prefer the part of the plant which is in front of the FX5 outlet. He sways back and forth, the food won't stay in one spot long enough for him to get it. I'll continue to keep an eye on him. If he doesn't appear to be eating I might move him to the breeder box. I've only had him for 2 days, just trying to think ahead.

The little guy ate last night. He was hanging out at the top like usual and I placed a couple 1mm floating pellets in front of him. He managed to get two of them.

The Endli's are pigs.. Hopefully I'll see some great growth out of them.

Well one of the Endli's ended up eating the smaller Delhezi.

The Endli's are maybe 4-4.5" and the Delhezi was 2-2.5". I saw one Endli swim from one side of the tank to the other fairly quickly so I went over to see what was going on and I saw a tail sticking out of his mouth.